Science 10 English

8/19/2019 Science 10 English

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SUPPORT MATERIAL

CLASS-X

SCIENCE

2012 - 2013

Venue :

R.P.V.V., Sector-XI, Rohini, Delhi

Published by :

Directorate of Education Govt. of NCT of Delhi


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List of Members who prepared Support MaterialFor Science for Class-X

Group Leader

Mr. Rajpal Sherawat

Principal, R.P.V.V., Sec.-XI, Rohini,Delhi

Sl . No. Nam D esi gnati on Name of the School

1. Ms. Sadaf Fatima Merchant T.G.T. (N. Sc.) R.P.V.V., Sec.-XI,Rohini,Delhi

2. Mr.Anil Kumar Nirwal T.G.T. (N.Sc.) R.P.V.V., Sec.-XI,

Rohini,Delhi

3. Mr. Siddharth Kaushik T.G.T. (N.Sc.) R.P.V.V., Civil Lines,

Delhi

4. Ms. Jyoti Puri T.G.T. (N.Sc.) S.K.V., Kamdhenu,

D-Block, Mangolpuri,

Delhi

5. Ms. MeenakshiTyagi T.G.T. (N.Sc.) G. Co.ed.S.S.S.,

Sec.-XI,Rohini, Delhi


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List of Contents

Chapter Name of th Pag

N o. Chapter No.

1. ChemicalReactionsand Equations

2. Acid, Bases and Salts

3. Metals and Non Metals

4. Carbon and its compound

5. Periodic ClassificationofElements

6. Life Processes

7. Control and Coordination

8. How do Organisms Reproduce

9. Heredity and Evolution

10. Light -Reflection andRefraction

11. Human eyeand colourfulWorld

12. Electricity

13. Magnetic effects of Electric Current

14. Sources of Energy

15. Our Environment

16. Management of Natural Resources


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CHAPTER – 1

SECTION A : READING

Chemical Reaction : – Whenever a chemical change occurs we can say that

a chemical reaction has taken place

eg – Food gets digested in our body

– Rusting of iron.

Chemical Equation :– A chemical reaction can be expressed symbolically

by using chemical equation

eg magnesium is burnt into air to form magnesium oxide can be represented

as

Mg + O2 →

MgO

– We can observe or recognise a chemical reaction by observing change

in state, colour, by evolution of gas or by change in temperature.

Physical state of the reactant and products are mentioned to make chemical

reaction more informative. eg we use (g) for gas, (l) for liquid, (s) for solid

and (aq) for aqueous.

Balancing Equation :– We balance the chemical equation so that no. of

atoms of each element involved in the reaction remain same at the reactant

and product side.

eg Fe + H2O → Fe2O3 + H2 can be written as

3 Fe(s) + 4H2O(g) → Fe2O3(s) +4H2(g)

Combination Reaction :– The reaction in which two or more substances

combine to form a new single substance


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eg CaO(s) + H2O(l → Ca(OH)2 (aq)Calcium Water Calcium hydroxide

oxide (slaked lime)

Quick lime

– Ca(OH)2

slaked lime is used for white washing walls. It reacts will CO2

to

form CaCO3

and gives a shiny finish to the walls.

Ca(OH)2

(aq)+

CO2

(g) → CaCO

3(s)

+ H

2O (l )

Calcium Calcium

hydroxide Carbonate

– Burning of Coal

C(s)

+ O2(g)

→ CO2(g)

+ heat + light

– Formation of water

2H2(g)

+ O2(g)

→ 2H2O(l )

Exothermic Reactions :– Reaction in which heat is released along with the

formation of products.

eg. CH4(g)

+ 2O2(g)

→CO2(g)

+ 2H2O

(g)

– Respiration is also exothermic reaction.

– De composition of vegetable matter into compost.

De compositon Reactions :– The reaction in which a single substance

decomposes to give two or more substances. De composition reactions can

be of three types

Thermal Decompositon :– When a decompositon reaction is carried out by

heating


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– Silver bromide behaves similarly

2Ag Br →Sunlight 2Ag(s) + Br

2(g)

– The above two reactions are used in black and white photography.


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– Endothermic Reactions – The reactions which require energy in the formof heat, light or electricty are called Endothermic Reactions.

2Ba(OH)2

+ NH4Cl → 2BaCl

2 + NH

4OH

– Displacement Reaction : The chemical Reaction in which an element

displaces another element from its solution

Fe(s)

+ CuSO4(aq)

→ FeSO4

+ Cu(s)

Copper (aq)

Sulphate Iron Sulphate

– The nail becomes brownish in colour and the blue colour of Copper Sulphate

solution fade.

– Other examples Zn(s)

+ CuSO4 → ZnSO

4 + Cu

(s)(aq) (aq)

Copper Zinc

Sulphate Sulphate

Pb(s) + CuCl2 →

PbCl2 + Cu(s)

(aq) (aq)

Copper Lead

Chloride Chloride

– Zinc and lead are more reactive elements than copper. They displace copper

from its compounds.


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– Double Displacement Reaction : The reaction in which two different atomsor group of atoms are mutually exchanged

eg. Na2

SO4

+ BaCl2 → BaSO

4(s) + 2NaCl

(aq) (aq) (aq)

Sodium Barium Barium Sodium

Sulphate Chloride Sulphate Chloride

A white substance is formed due to above reaction. The insoluble substance

is called precipitate.

Precipitation Reaction – Any reaction that produces a precipitate is called a

precipitation reaction.

eg. Pb(NO3)

2 + 2KI → PbI

2 +2KNO

3(aq) (aq) (aq)

Lead Nitrate Potassium Lead PotassiumIodide Iodide Nitrate

– Oxidation : Oxidation is the gain of oxygen or loss of hydrogen

eg. 2Cu + O2 →

Heat 2CuO

When Copper is heated a black colour appears. If this CuO is reacted with

hydrogen gas then again Cu becomes brown as reverse reaction takes placeCuO + H

2 →Heat Cu + H

2O

– Reduction : Reduction is the loss of oxygen or gain of hydrogen.

– Redox Reaction : The reaction in which one reactant gets oxidised while

other gets reduced

eg. ZnO + C → Zn + CO

MnO2

+ 4HCl → MnCl2

+ 2H2O + Cl

2


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– Corrosion : When a metal is attacked by substances around it such asmoisture, acids etc.

eg. Reddish brown coating on iron.

(ii) Black coating on Silver.

– Rancidity : When fats and oils are oxidised they become rancid and their

smell and taste change.

– Antioxidants are added to foods containing fats and oil.

EXERCISE

(Question Bank)

(1 Mark)

Answer the following questions very breifly

1. What happens when the milk is left at room temperature during summer?

2. Write a chemical equation when magnesium is burnt in air to give magnesium

oxide.

3. A substance under goes chemical reactions to produce simpler products,

what type of reaction is this?

4. Why do copper vessels lose their shine when exposed to air?

5. Which gas is produced by the action of dilute hydrochloric acid on zinc

granules?

6. Fe2O

3 + 2Al → Al

2O

3 + 2Fe

The above reaction is an example of which type of reaction.

7. Name the type of reaction in which energy is absorbed.

8. Why does the colour of copper sulphate solution change when an iron nail is

dipped into it?

9. Give an example of decomposition reaction which proceeds by absorbing

electric energy.

10. Why do we balance the chemical equation?


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Answer the following questions briefly (2 mark)

1. Write down the observations which indicate the occurence of a chemical

reaction.

2. Why is respiration considered as an exothermic reaction? Explain.

3. Transfer the following statements into Chemical equations and then balance

them.

a) Hydrogen gas combines with nitrogen to form ammonia.

b) Potassium metal reacts with water to give potassium hydroxide and

hydrogen gas.

4. Identify the substances that are oxidised and the substances that are reduced

to the folllowing reactions.

1. Na + O2 → Na

2O

(s) (g) (s)

CuO + H2

→ Cu + H2

O(l

(s) (g) (s)

5. What happens when silver chloride is exposed to sunlight? Give one practical

application of this reaction. Write the equation also.

6. Why is the bag used for potato chips flushed with nitrogen gas?

Answer the following questions in detail (3 marks)

1. Write down the balanced chemical equations for the following reactions.

a) Zinc Carbonate(s) → Zinc Oxide + Carbon Dioxide

(g)

b) Aluminium(s)

+ Chlorine(g) → Aluminium Chloride

(s)

c) Magnesium(s)

+ Water (l →

Heat Magnesium Hydroxide(l

+ Hydrogen(g)

2. Choose combination, displacement and double displacement reactions out of the given reactions.

i) MnO2

(s)+ 4HCl

(l →MnCl

2(s)

+ Cl2

(g)+ 2H

2O

(l

ii) CaO(s)

+ CO2

(g) → CaCO

3(s)

iii) 2AgCl(s) → 2Ag

(s) + Cl

2(g)


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3. What happens when CO2(g)

is passed through slaked lime? Write the balancedchemical equation. Write the type of reaction that has occured.

Explain the following questions detail (5 marks)

1. Balance the following chemical equation and identify the type of reaction they

represent

KClO3 → KCl + O

2

NH3

+ O2 → NO + H

2O

Na2O + H

2O → NaOH

Na + H2O → NaOH + H

2

FeCl3

+ NaOH → Fe (OH)3

+ NaCl.

2. Define various types of chemical reactions. Write one chemical equation for

each type.


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CHAPTER – 2

ACIDS, BASES AND SALTS

Acids Bases

– Sour in taste – Bitter in taste – Change the blue litmus to red – Change red litmus to blue

– eg.HydrochloricAcid HCl eg. Sodium hydroxide NaOH

– SulphuricAcid H2SO

4 Potassium hydroxide KOH

– NitricAcid HNO3

Calcium hydroxide Ca(OH)2

– Acetic Acid CH3

COOH – Ammonium hydroxide NH4OH

Some Naturally occuring acids

Vinegar – Acetic Acid

Orange – Citric Acid

Lemon – Citric Acid

Tamarind – Tartaric Acid

Tomato – Oxalic Acid

Sour milk (Curd) – Lactic Acid

Ant and Nettle sting – Methanoic Acid

Acid – Base Indicators – Indicate the presence of an acid or base in a

solution.

Litmus solution – It is a natural indicator. It is a purple day extracted fromLichens. Other examples are Red Cabbage and coloured petals of Petunia

and turmeric.

Olfactory indicators – Show odour changes in acidic or basic media. eg.

onion and clove.


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Acid – Base Indicators

S. No. Name of the Colour Change Colour Change

Indicator ith Acid ith Base

A. Blue litmus solution To red No change

B. Red litmus solution No change To blue

C. Turmeric No change To red

D. Methyl orange To red To yellow

E. Phenolphthalein (colourless) No change To pink

Dilute Acid : Contains only a small amounts of acid and a large amount of

water.

Concentrated Acid : A concentrated acid contains a large amount of acid and

a small amount of water.

Chemical Properties of Acids and Bases

Acid + Metal → Salt + Hydrogen

(Refer activity 2.3 on page No. 19 of NCERT Book)

2HCl + Zn → ZnCl2 + H2

2HNO3

+ Zn → Zn (NO3)

2 + H

2

H2SO

4 + Zn → ZnSO

4 + H

2

2CH3COOH + Zn → (CH

3COO)

2 Zn + H

2

Pop test : When a buring candle is brought near a test tube containing

hydrogen gas it burns with a ‘Pop’ sound. This test is conducted for examining

the presence of hydrogen gas.

Base + Metal → Salt + Hydrogen

NaOH + Zn → Na2ZnO

2 + H

2

Sodium Zincate

Note – Such reactions are not possible with all the metals.


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Action of Acids with metal Carbonates and metal bicarbonates

Metal Carbonate + Acid → Salt + Carbondioxide + Water

Na2CO

3(s)

+ 2HCl(aq)

→ 2NaCl(aq)

+ H2O(l ) + CO

2(g)

Metal bicarbonate + Acid → Salt + Carbondioxide + Water

NaHCO3

+ HCl → NaCl + CO2

+ H2O

Lime water Test : On passing the CO2

gas evolved through lime water,

Ca(OH)2

(aq) + CO2(g)

→ CaCO3(s)

+ H2O(l )

Lime water White precipitate

On passing excess CO2

the following reaction takes place

CaCO3(s)

+ H2O

(l + CO

2(g) → Ca(HCO

3)

2 aq

Soluble in water

Neutralisation Reactions

Base + Acid → Salt + Water

NaOH(aq)

+ HCl(aq)

→ NaCl(aq)

+ H2O(l )

Neutralisation reacton takes place when the effect of a base is nullified by

an acid and vice versa to give salt and water.

Reactions of metal oxides with acids

Metal Oxide + Acid → Salt + Water

CuO + HCl → CuCl2

+ H2O

Copperoxide Hydrochloric Copper + Water

acid chloride

Note : Appearance of blue green colour of the solution because of formation

of CuCl2.

Metallic oxides are said to be basic oxides because they give salt and water

on reacting with acids.

Reaction of Non Metallic Oxide with Base

Non metallic oxide + Base → Salt + Water

Ca(OH)2

+ CO2 → CaCO

3 + H

2O


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Note : Non Metallic oxides are said to be acidic in nature because on reactingwith a base they produce Salt and Water.

All acidic solutions conduct electricity

Refer activity 2.3 on page 22 of NCERT Book

– Glowing of bulb indicates that there is a flow of electric current through the

solution.

Acids or bases in a Water Solution

Acids produce H+ions in the presence of water

HCl + H2O → H

3O+ + Cl –

H3O+ – Hydronium ion.

– H+ion cannot exist alone. It exists as H+(aq) or (H3O+) hydronium ion.

H+ + H2O → H

3O+

– Bases provide (OH – ) ions in the presence of water

NaOH(s) →

2H O Na+(aq)

+ OH – (aq)

KOH(s) →2H O K +(aq) + OH – (aq)

Mg(OH)2(s) →

2H O Mg2+(aq) + 2OH – (aq)

Alkalis

All bases donot dissolve in water. An alkali is a base that dissolves in water.

Common alkalis are

NaOH Sodium hydroxide

KOH Potassium hydroxide

Ca(OH)2

Calcium hydroxide

NH4OH : Ammonium hydroxide

Note : All alkalis are bases but all bases are not alkalis.

Precaution must be taken while mixing acid or base with water. The acid must

always be added to water with constant stirring as it is highly exothermic

reaction.


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More about Salts

Salts and their derivation

S. No. Name of Salt Formula Derived from Derived from

1. Potassium Sulphate K 2

SO4

KOH H2SO

4

2. Sodium Sulphate Na2

SO4

NaOH H2SO

4

3. Sodium Chloride NaCl NaOH HCl

4. Ammonium Chloride NH4Cl NH

4OH HCl

Note : NaCl and Na2 SO4 belong to the family of sodium salts as they havethe same radicals. Similarly NaCl and KCl belong to the family of chloride

salts.

Importance of pH in our daily life

Importance of pH in our digestive system – pH level of our body regulates

our digestive system. In case of indigestion our stomach produces acid in a

very large quantity because of which we feel pain and irritation in our stomach.

To get relief from this pain antacids are used. These antacids neutralises the

excess acid and we get relief.

pH of Acid Rain : When pH of rain water is less than 5.6 it is called Acid

Rain.When this acidic rain flows into rivers these also get acidic, which causes

a threat to the survival of aquatic life.

pH of Soil : Plants require a specific range of pH for their healthy growth. If

pH of soil of any particular place is less or more than normal than the farmers

add suitable fertilizers to it.

Our body functions between the range of 7.0 to 7.8 living organisms can

survive only in the narrow range of pH change.

Tooth decay and pH : Bacteria present in the mouth produce acids bydegredation of sugar and food particles remaining in the mouth. Using toothpaste

which is generally basic can neutralise the excess acid and prevent tooth

decay.

Bee sting or Nettle sting contains methanoic acid which causes pain and

irritation. When we use a weak base like baking soda on it we get relief.


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Neutral Salts : Strong Acid + Strong base pH value is 7

eg. NaCl, CaSO4

Acidic Salts : Strong Acid + weak base

pH value is less than 7

eq. NH4Cl, NH

4 NO

3

Basic Salts : Strong base + weak acid

pH value is more than 7

eg. CaCO3, CH

3 COONa

Chemicals from Common Salt

– Sodium chloride is called as common salt used in our food. It is derived

from seawater.

– Rock Salt is the brown coloured large crystals. This s mined like coal.

– Common Salt is an important raw material for many materials of daily use

such as.

Sodium hydroxide

Washing Soda

Bleaching Power.

Sodium Hydroxide

Preparation : Prepared by the method called chlor-alkali

Called chlor-alkali because we get chlorine and a base in this.

2NaCl(aq)

+ 2H2O(l ) → 2NaOH

(aq) + Cl

2(g) + H

2(g)


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Bleaching Power

Preparation → Ca(OH)2

+ Cl2 → CaOCl

2 + H

2O

calcium hydroxide chlorine bleaching water

power

uses in textile, factories and laundry, used as disinfectant

Baking Soda

– Common name – Sodium Hydrogen Carbonate

Preparation NaCl + H2O + CO

2 + NH

3 → NH

4Cl + NaHCO

3

Sodium Water Carbon Ammonia Sodium hydrogen

chloride dioxide carbonate

On heating NaHCO3

produces :

NaHCO3 →

Heat Na2CO

3 + H

2O + CO

2

CO2

produced causes dough to rise and make cakes, pastries spongy.

Uses : In household, ingredients of antacid

In making baking power

On heating baking powder produces

NaHCO3

+ H+ → CO2

+ H2O + Sodium Salt of acid

Washing Soda

Preparation : Recrystallisation of sodium carbonate

Na2CO

3 + 10H

2O →

Heat Na2CO

3. 10H

2O

Uses

– Used in glass, soap and paper industry

– Cleaning agent for domestic purposes.

– Removal of hardness of water.

– Manufacturere of borax.

Water of crystallisation : Fixed no. of water molecules present in one formula

unit of a salt.

– On heating copper sulphate crystals water droplets appear, formula of

hydrated copper sulphate – CuSO4. 5H

2O.


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– gypsum also contains water of crystallisation.

– Formula of gypsum – CaSO4.2H

2O

– On heating gypsum at 373k it becomes CaSO4.½H

2O is plaster of

paris.

– Plaster of Paris is used as plaster for fractured bones.

– When plaster of Paris is mixed with water it changes to gypsum.

CaSO4.½ H

2O + 1½ H

2O → CaSO

4.2H

2O

Uses of plaster of Paris : Making toys, decorative material and smooth surfaces.

EXERCISE

(Question Bank)

Very Short answer type questions (1 mark)

1. Two solution have pH number 4 and 9 respectively which solution has more

H+ ion concentration?

2. Why should cured and sour substances not be kept in brass and copper

vessel?

3. What is the chemical name of bleaching powder?

4. Write down the molecular formula for one strong and one weak acid.

5. Explain why plaster of Paris should be stored in a moisture proof container?

6. Name the gas evolved when dil. sulphuric acid acts on sodium carbonate.

7. What is the use of common salt in soap industry?

8. What do you observe when a buring candle is brought near the testube

containing hydrogen gas?

9. Name the indicator used to measure pH values over the whole range.

10. Write the formula of washing powder.

Short Answer Type Questions (2 marks)

1. Write two physical properties of an acid

2. Complete the reaction CaCO3

+ H2O → name the products formed.


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3. A testtube contains solution of NaOH and Phenolphthalein. Why the colour of the solution changes when HCl in added to it.

4. Why metallic oxides are called as basic oxides and non-metallic oxides are

calles acidic oxides?

5. In a beakey a solution of HCl is poured and an electric circuit containing bulb

is placed systemtically. What happens to the bulb and why?

What will happen if HCl is repplaced by NaOH?

6, Identify the type of reaction

H X + M OH → MX + HOH

7. Why all bases are not alkalies but all alkalis are bases?

Answer the following questions in detail (3 marks)

1. What is acid rain? What is its pH? How does it affect the aquatic life?

2. What happens when a metal react with dilute hydrochloric acid? Write the

reaction

© NaOH + Zn → _________ + _________.

3. What happens when an acid or a base is added to the water? Why does the

beaker appear warm? Why should we always add acid or base to the water

and not water to the acid or base.

Answer the following question in detail (5 marks)

1. (a) Write down five products formed with the help of common salt on

industrial level.

(b) Write down the chemical name of these compounds and one use of

each of them.

2. Fill in the blanks

a) Acid + ______ → Salt + Water..

b) _____ + Metal → Salt + _____

c) Metal carbonate / metal hydrogen carbonate + acid

→ _______ + _______ + _______.

d) NaOH →2H O _______ + _______

e) Na2CO

3 + 10H

2O → _______.


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CHAPTER – 3

METALS AND NON-METALS

About 118 elements are known today. There are more than 90 metals, 22

non metals and a few metalloids.

Sodium (Na), potassium (K), magnesium(Mg), aluminium(Al), calcium(Ca),

Iron(Fe), Barium(Ba) are some metals.

Oxygen(O), hydrogen(H), nitrogen(N), sulphur(S), phosphorus(P), fluorine(F),

chlorine(Cl), bromine(Br), iodine(l) are some non-metals

*Physical properties of metals:

Solid at room temperature except mercury

Ductile (drawn into wires)

Malleable (beaten into thin sheets)

Sonorous(produce sound)

Lustrous(natural shine)

Have high melting point. Cesium and gallium have very low melting point.

Generally good conductor of heat and electricity, except lead and mercury

which are comparatively poor conductors. Silver and copper are best

conductors.

Have high density. Sodium and potassium can be cut with knife, they have

low density.Physical properties of non-metals:

Occur as solid or gas. Bromine is liquid.

Generally bad conductors of heat and electricity. Graphite a natural form of

carbon is a good conductor.

Non-sonorous.


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Non-lustrous, only iodine has lustre.

Metals form basic oxides like Magnesium oxide(MgO), while non-metals

form acidic oxides (as in acid rain).

*Chemical properties of metals:

1. Reaction with air

Metals can burn in air, react or don't react with air.

Metal + oxygen → Metal Oxide

Some metals like Na and K are kept immersed in kerosene oil as they react

vigorously with air and catch fire.

Some metals like Mg, Al, Zn, Pb react slowly with air and form a protective

layer.

Mg can also burn in air with a white dazzling light to form its oxide

Fe and Cu don't burn in air but combine with oxygen to form oxide. When

heated iron filings burn when sprinkled over flame.

Metals like silver, platinum and gold don't burn or react with air.

2Na + O2

→ Na2O

2Mg + O2

→ 2MgO

2Cu + O2

→ 2CuO

4Al + 302

→ 2Al2O

3

Amphoteric Oxides : metal oxides which react with both acids as well as

bases to form salt and water e.g. Al2O

3, ZnO.

Al2O

3 + HCl → AlCl

3 + H

2O

Al2O

3 + NaOH → NaAlO

2 + H

2O

2. Reaction with water :


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Na + H2O → NaOH + H2

K + H2O → KOH + H

2

Ca + H2O → Ca(OH)

2 + H

2

Mg + H2O → Mg(OH)

2 + H

2

In case of Ca and Mg, the metal starts floating due to dubbles of hydrogen

gas sticking to its surface.

Al + H2O → Al

2O

3 + H

2

Fe + H2O → Fe

3O

4 + H

2

Try Balancing these Chemical equations yourself

3. Reaction with dilute acids:

Metal + dilute acid → Salt + Hydrogen gas

Metals react with dilute hydrochloric acid and dilute sulphuric acid to form

salt and hydrogen gas.

Fe + 2HCl → FeCl2

+ H2

Mg + 2HCl → MgCl2

+ H2

Zn + 2HCl → ZnCl2 + H2

2Al + 6HCl → 2AlCl3

+ 3H2

Copper, mercury and silver don’t react with dilute acids.

Hydrogen gas produced is oxidised to water when metals react with nitric

acid. But Mg and Mn, react with very dilute nitric acid to evolve hydrogen

gas.

Mg + 2HNO3 → Mg(NO

3)

2 + H

2

4. Reaction of metals with other metal salts :

Salt Salt

Metal A + solution → solution + Metal B

of B of A

All metals are not equally reactive. Reactive metals can displace less reactive

metals from their compounds in solution. This forms the basis of reactivity

series of metals.


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Reactivity series is a list of metals arranged in order of their decreasingactivities.

Fe + CuSO4

→ FeSO4

+ Cu

Zn + CuSO4

→ ZnSO4

+ Cu

Reaction between Metals and Non-Metals :

– Reactivity of elements can be understood as a tendency to attain a completely

filled valence shell.

– Atom of metals can lose electrons from valence shells to form cations (+ve

ions).

– Atom of non-metals gain electrons in valence shell to form anions (–ve ions).

– Oppositely charged ions attract each other and are held by strong electrostatic

forces of attraction forming ionic compounds.

Formation of MgCl2

Mg → Mg2+ + 2e –

2,8,2 2,8 (Magnesium ion)

Cl2

+ 2e – → 2Cl –

2,8,7 2,8,8 (Chloride ion)


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Properties of Ionic Compounds :

– Are solid and mostly brittle.

– Have high melting and boiling points. More energy is required to break the

strong inter-ionic attraction.

– Generally soluble in water and insoluble in kerosene, petrol.

– Conduct electricity in solution and in molten state. In both cases, free ions are

formed and conduct electricity.

Occurance of Metals

Minerals : elements of compounds occuring naturally are minerals.

ORES : mineral from which metal can be profitably extracted is an ore. For example,sulphide ore, oxide ore, carbonate ore.

– Metals at the bottom of activity series like gold, platinum, silver, copper

generally occur in free state. But copper and silver also occur in sulphide and

oxide ores.

– Metals of medium reactivity (Zn, Fe, Pb etc.) occur mainly as oxides, sulphides

or carbonates.

– Metals of high reactivity (K, Na, Ca, Mg and Al) are very reactive and thus

found in combined state.

GANGUE : ores are naturally found mixed impurities like soil, sand, etc. called

gangue. The gangue is removed from the ore.

METALLURGY : step-wise process of obtaining metal from its ore.

*Enrichment of ore

*Obtaining metal from enriched ore.

*Refining of impure metal to obtain pure metal.


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Extracting Metals Low in the Activity Series :

By heating the ores in air at high temperature.

*Mercury from cinnabar

2HgS + 3O2 →

Heat 2HgO + 2SO2

2HgO →

Heat 2Hg + O2

* Copper from copper sulphide

Cu2S + 3O

2 →

Heat 2Cu2O _ 2SO

2

2Cu2O + Cu

2S →

Heat 6Cu + SO2

Extracting Metals in the Middle of Activity Series :

*Metals are easier to obtain from oxide ores, thus, sulphide and carbonate ores are

converted into oxides.

*Metal ore heated strongly in excess of air (Roasting)

2ZnS + 3O2 →

Heat 2ZnO + 2SO2

Metal ore heated strongly in limited or no supply of air (Calcination)

ZnCO3 →

Heat ZnO + CO2

Reduction of Metal Oxide :

1. USING COKE: Coke as a reducing agent.

ZnO + C →

Heat Zn + CO

2. USING DISPLACEMENT REACTION : highly reactive metal like Na, Ca

and Al are used to displace metals of lower reactivity from their compounds.

MnO2

+ 4Al →

Heat 3Mn + 2Al2O

3 + heat

Fe2O

3 + 2Al

→Heat 2Fe + Al

2O

3 + heat

– In the above reaction molten iron is formed and is used to join railway tracks.

This is called thermit reaction.


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Extracting Metals at the Top of Activity Series :

These metals

– have more affinity for oxygen than carbon.

– are obtained by electrolytic reduction. Sodium is obtained by electrolysis of

its molten chloride NaCl → Na+ + Cl –

As electricity is passed through the solution metal gets deposited at cathode

and non-metal at anode.

– At cathode :

Na+ + e – → Na

– At anode :

2Cl – → Cl2

+ 2e –

Refining of Metals :

– Impurities present in the obtained metal can be removed by electrolytic refining.

Copper is obtained using this method. Following are present inside the

electrolytic tank.

– Anode – slab of impure copper – Cathode – slab of pure copper

– Solution – aqueous solution of copper sulphate with some dilute sulphuric

acid

– From anode copper ions are released in the solution and equivalent amount

of copper from solution is deposited at cathode.

– Impurities containing silver and gold gets deposited at the bottom of anode

as anode mud.


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Corrosion :

– Metals are attacked by substances in surroundings like moisture and acids.

– Silver - it reacts with sulphur in air to form silver sulphide and articles become

black.

– Copper - reacts with moist carbon dioxide in air and gains a green coat of

copper carbonate.

– Iron-acquires a coating of a brown flaky substance called rust. Both air and

moisture are necessary for rusting of iron.

Prevention of corrosion:

– Rusting of iron is prevented by painting, oiling, greasing, galvanizing, chrome plating, anodising and making alloys.

– In galvanization, iron or steel is coated with a layer of zinc because zinc is

preferably oxidized than iron.

Alloys : These are mixture of metals with metals or non-metals

– Adding small amount of carbon makes iron hard and strong.

– Stainless steel is obtained by mixing iron with nickel and chromium. It is hard

and doesn’t rust.

– Mercury is added to other metals to make amalgam.

Bras : alloy of copper and zinc.

Bronz : alloy of copper and tin.

– In brass and bronze, melting point and electrical conductivity is lower than

that of pure metal.

Solder : alloy of lead and tin has low melting point and is used for welding

electrical wires.

Question Bank 1 MARK

1 Name a metal which is the best conductor of electricity and one which is poor conductor of electricity.

2 Why food cans are coated with tin and not with zinc?

3. Name any two alloys whose electrical conductivity is less than that of pure

metals.

4. Name the non-metal with lustre.

5. Define amphoteric oxide.


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6. An aqueous solution of Al2O3 is electrolysed. Name the element collected atanode.

7. An oxide of an element was dissolved in water. The final solution turned red

litmus blue. Is the element metal, non-metal or a metalloid?

8. What happens when cinnabar is heated?

9. Ionic compounds have high melting point. Why?

10. Name two metals which are found in nature in free state.

2 MARKS

1. Why Magnesium and calcium float when they react with water?

2. Write the chemical equations of heating of Cu and Fe.

3. Write two chemical equations to show that Al2O

3 is an amphoteric oxide.

4. What is galvanization? Why it is done?

5. Hydrogen gas is not evolved generally when metals react with nitric acid.

Explain.

6. Explain the thermit process. Write the chemical equation involved.

7. Distinguish between roasting and calcination.

8. Every ore is a mineral but not every mineral is an ore. Explain.

9. Why highly reactive metals can't be obtained from their oxides using coke as

a reducing agent?

3 MARKS

1. Diagrammatically show the formation of MgO.

2. Ionic compounds are good conductors of electricity under specific conditions.

Name the two conditions and give reasons.

5 MARKS

1. i) What is reactivity series of metals? Arrange the metals zinc, magnesium,

aluminium, copper and iron in a decreasing order of reactivity.ii) What is observed when you put

a) Some zinc pieces into blue copper sulphate solution.

b) Some copper pieces into green ferrous sulphate solution.

iii) Name a metal which combines with hydrogen gas. Name the compound

formed.


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2. Give reasons:

i) Platinum, gold and silver are used to make jewellery.

ii) Sodium and potassium are stored under oil.

iii) Aluminium is a highly reactive metal, still it is used to make utensils for

cooking.

iv) Carbonate and sulphide ores are usually converted into oxides during

the process of extraction.

METALS AND NON-METALS

IN BRIEF

– Metals are generally solid, sonorous, lustrous, good conductor of heat and

electricity, malleable, ductile, high melting point, high densities, form basic

oxides, form +vely charged ion.

– Non-metals are generally solid or gas, non-lustrous, non-sonorous, bad

conductor of heat and electricity, have low melting point, form acidic oxides

and form -vely charged ions.

– Metals like Na, K and Ca are highly reactive, while others like Magnesium,

Aluminium, Zinc and Lead are less reactive and some others are least reactive

like silver, gold and platinum.

– Metals generally displace hydrogen from acids.

– Reactivity series is based on displacement capability of metals and is a series

of metals in the order of their decreasing reactivity.

– Metals and non-metals react to form ionic compounds which are soluble in

water, have high melting point and are good conductor of electricity in their

aqueous solution or molten state.

– Ores are minerals from which a metal can be profitably extracted.

– Metals are extracted from their ores according to their reactivity.

– Sulphide and chloride ores are roasted while carbonate ores are roasted.

– Pure metals can be obtained using electrolytic refining process.

– Metals are generally attacked by air and corrode. To alter the properties of

metals alloys are made.

– Steel, stainless steel, amalgams, brass, bronze and solder are some alloys.


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CHAPTER – 4

CARBON AND ITS COMPOUNDS

Carbon is a versatile element.

In earth’s crust, carbon is 0.02% and found in form of minerals.

Atmosphere has 0.03% of Carbon dioxide.

All living structures are carbon based.

Covalent Bond in Carbon

– The atomic number of carbon is 6 and its electronic configuration is 2, 4. To

attain a noble gas configuration it can

1. Gain 4 electrons. But it would be difficult for nucleus to hold 4 extra electrons.

2. Lose 4 electrons. But it would require a large amount of energy to remove

4 electrons.

– It is difficult thus for an atom of carbon to either gain or lose electrons.

– Carbon attains the noble gas configuration by sharing its valence electrons

with other atoms. Atoms of other elements like hydrogen, oxygen, nitrogen,

chlorine also show sharing of valence electrons.

– Formation of H2, O

2 and N

2 is shown as below :


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– It is evident that the number of shared pair of electrons can be one, two or three. Try making the structures of H

2O and CH

4.

– Bond formed by the sharing of an electron pair between two atoms is called

covalent bond.

– Covalently bonded molecules have low melting and boiling points because of

comparatively weaker intermolecular forces, unlike ionic compounds.

– These molecules are generally poor conductor of electricity since no charged

particles are formed.

Versatile Nature of Carbon Atoms:Two important properties of carbon atom enable carbon to form enormously large

number of compounds.

CATENATION : property of carbon atom to form bond with other atoms of

carbon is called catenation. Like carbon, silicon forms compounds with hydrogen

upto seven or eight atoms of silicon.


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TETRAVALENCY : Having a valency of 4, carbon atom is capable of bondingwith atoms of oxygen, hydrogen, nitrogen, sulphur, chlorine and other elements.

The smaller size of carbon atom enables nucles nucleus to hold the shared pair of

electrons strongly, thus carbon compounds are very stable in general.

Saturated and Unsaturated Carbon Compounds

– ALKANE : Cn

H2n+2

– ALKENE : Cn

H2n

– ALKYNE : Cn

H2n–2

– Electron dot structure of a saturated carbon compound, ethane is as follows:


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– Electron dot structure of an unsaturated cabon compound, ethene is as follows:

TRY DRAWING THE ELECTRON DOT STRUCTURE OF ETHYNE

Formulae and Structures of Saturated Compounds of Carbon and Hydrogen


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On the basis of structures the hydrocarbons can be:

Stru ctural isomers : these are the compounds having identical molecular formula

but different structures. For example, isomers of butane.

Heteroatom and Functional Group :

*In hydrocarbon chain, one or more hydrogen atoms can be replaced by other

atoms in accordance with their valencies. The element that replaces hydrogen is

called a heteroatom.

*These heteroatoms and the group containing them impart chemical properties to

the compound and hence are called functional groups.


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Homologous Series:

– It is a series of compounds in which the same functional group substitutes for

hydrogen in a Carbon chain.

– For instance, the ALCOHOLSs: CH3

OH, C2H

5 OH, C

3H

7 OH, C

4H

9 OH.

– The successive member differs by –CH2-; unit and 14 units of mass.

– The chemical properties are imparted by the functional group thus all members

have similar chemical properties. But the members have different physical properties.

– The physical properties vary among the members of homologous series due

to difference in their molecular mass.

– Melting point and boiling point increases with increasing molecular mass.

Nomenclature of Carbon Compounds:

1. Identify the number of carbon atoms in the compound.

2. Functional group is indicated either by prefix or suffix.

Functional Group Suffix Prefix

Alkene eneAlkyne yne

Alcohol ol

Aldehyde al

Ketone one

Carboxylic acid oic acid

chlorine chloro


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3. If a suffix is added, then final ‘e’ is removed from the name eg. methanol(methane-e = methan + ol).

Chemical properties of Carbon compounds :

1. COMBUSTION :

*Carbon compounds generally burn (oxidize) in air to produce carbon dioxide and

water, and release heat and light energy.

CH4

+ O2 → CO

2 + H

2O + heat and light

*Saturated hydrocarbon burns generally with a blue flame in good supply or air andwith a yellow sooty flame in limited supply of air.

*Sooty flame is seen when unsaturated hydrocarbons are burnt.

*Burning of coal and petroleum emits oxides of sulphur and nitrogen which are

responsible for acid rain.

2. OXIDATION :

*Alcohols can be converted to carboxylic acids by oxidizing them using alkaline

potassium permanganate or acidified poatassium dichromate (they add oxygen to

the reactant, thus are called oxidizing agents).

43 2 3

2 2 7

Alkaline KMnO + heatCH - CH OH CH COOH

Acidified K Cr O + heat

3. ADDITION REACTION:

Hydrogen is added to unsaturated hydrocarbon in presence of palladium or nickel

as catalyst.

Vegetable oils are converted into vegetable ghee using this process.

Saturated fatty acids are harmful for health and oils with unsaturated fatty acids

should be used for cooking.


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4. SUBSTITUTION REACTION :

In saturated hydrocarbons, the hydrogen attached to carbon can be replaced by

another atom or group of atoms in presence of sunlight.

CH4

+ Cl2 → CH

3Cl + HCl (sunlight required)

IMPORTANT CARBON COMPOUNDS : Ethanol and Ethanoic Acid

Ethanol :

*Consumption of dilute ethanol causes serious health issues and intake of pure

alcohol is lethal.

CHEMICAL PROPERTIES OF ETHANOL

C2H

5OH Reacts with Sodium

to from Sodium Ethoxide andHydrogen

Wh en C2

H5

O H i s Heated with

Concentrated Sulphuric Acid at 443k, It is Dehydrated to Ethene


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Ethanoic Acid (CH3COOH) / Acetic Acid :

*5-8% solution of acetic acid in water is called vinegar.

*Pure acetic acid is called glacial acetic acid.


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Esterification :

Carboxylic acids react with alcohols in presence of few drops of concentrated

sulphuric acid as catalyst and form sweet smelling compounds called ester.

Hydrolysis :

On heating with an acid or a base the ester forms back the original alcohol and

carboxylic acid.

CH3COO CH

2CH

3 + NaOH → CH

3COONa + CH

3-CH

2OH

CH3COO CH

2CH

3 →

2 4Dil.H SOHEAT

CH3COOH + CH

3-CH

2OH

*Alkaline hydrolysis of ester is also called saponification.

Soaps and Detergents

– Soap is sodium and potassium salt of carboxylic acids with long chain.

– Soaps are effective with soft water only and ineffective with hard water.

– Detergents are ammonium or sulphonate salts of carboxylic acids with long

chain. They are effective with both soft as well as hard water.

An ionic part (hydrophilic) and a long hydrocarbon chain (hydrophobic) part

constitutes the soap molecule.

Structure of a Soap Molecule

Cleansing Action of Soaps :

– Most dirt is oily in nature and the hydrophobic end attaches itself with dirt,

while the ionic end is surrounded with molecules of water. This result in

formation of a radial structure called micelles.


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– An emulsion is thus formed by soap molecule. The cloth needs to be

mechanically agitated to remove the dirt particles from the cloth.

– Scum : The magnesium and calcium salts present in hard water reacts with

soap molecule to form insoluble products called scum, thus obstructing the

cleansing action. Use of detergents overcome this problem as the detergent

molecule prevents the formation of insoluble product and thus clothes get

cleaned.

EXERCISE

(Question Bank)

1MARK

1. How an atom of carbon attain noble gas configuration?

2. Draw the electron dot structure of a molecule of water.

3. Define catenation.

4. The kerosene/gas stove used at home has inlets for air. Give reason.

5. Write only the chemical equation for dehydration of ethanol by hot conc.Sulphuric acid.

6. Write the number of covalent bonds present in propane.

7. Define the term: oxidising agent.

8. Write the formula for first member of ketone.


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9. Would you be able to check if water is soft by using a soap?

10. Write the molecular formula of an alkyne containing 10 atoms of hydrogen.

2 MARKS

1. Define saponification. Write a chemical equation for it.

2. Covalent compounds generally don't conduct electricity. Why?

3. Specify the condition in which ethanol undergo oxidation to form ethanoic

acid. Write the chemical equation.

4. Define isomerism. Draw the structures of the two isomers of butane.5. Identify the functional group present in the following compounds: HCOOH,

HCHO, CH3Br and C

10H

21OH

3 MARKS

1. What is a homologous series? Write any two characteristic features of any

homologous series using one example.

2. Write any three differences between soaps and detergents.

5 MARKS

1. Differentiate between ethanol and ethanoic acid on the basis of any three

physical properties and two chemical properties.

2. An organic compound 'A' is used as a preservative in pickles and has molecular

formula C2H

4O

2. This compound reacts with ethanol to form a sweet smelling

compound 'B'.

i) Determine the compound 'A'.

ii) Write the chemical equation for its reaction with ethanol to form

compound 'B'.

iii) Write any two uses of compound 'B'.

iv) Which gas is produced when compound 'A' reacts with washing soda?

Write the chemical equation

v) How can vinegar be obtained from compound 'A'?


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CARBON AND ITS COMPOUNDS IN BRIEF

– Carbon is a versatile non-metal.

– Carbon atom like atoms of other non-metals like oxygen, nitrogen, hydrogen

and chlorine shares electrons.

– Carbon forms large number of compounds due to catenation and tetravalency.

– Carbon can form single, double and triple covalent bonds.

– The compounds of hydrogen and carbon are called hydrocarbons, which can

be saturated or unsaturated.

– Structurally hydrocarbons can have straight chain, branches or cyclic structure.

– Difference in Structural arrangement of same molecule gives rise to isomerism.

– In a hydrocarbon, a heteroatom can replace the hydrogen atom and imparts

it chemical properties.

– Homologous series is a series of compounds with same general formula and

same chemical properties but different physical properties.

– Carbon based compounds are excellent fuels.

– Ethanol is an important industrial compound. It reacts with reactive metals andis also dehydrated to ethene.

– Ethanoic acid is another important compound. It combines with ethanol to

form sweet smelling esters.

– Soaps and detergents are used as cleansing agents. Detergents efficiently

cleanses with soft and hard water.


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CHAPTER – 5

PERIODIC CLASSIFICATION OF

ELEMENTS

Elements : Substances containing atoms of only one type. eg. Na, Au, Mg etc. – There are around 118 elements known to us.

Elements are classified to make the study easy.

Dobereiner’s Traids : When the elements were written in order of increasing

atomic masses the atomic mass of the middle was the average of the atomic

mass of the other two elements.

eg. Elements Atomic Mass

Ca 40.1

Sr 87.6Ba 136.3

Limitations : Only three triads were recognised from the elements known at

that time.

Atomic mass of an element is the relative mass of its atom as compared widh

the mass of a Carbon-12 atom taken as 12 units

Newland’s law of octaves :

– Based on increasing atomic mass of elements.

– When elements are arranged it was found that every eighth element had properties similar to that of the first. eg properties of sodium and Lithium are

the same.

Limitations :

– Applicable only upto Calcium

– Properties of new elements couldn’t fit in it.


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– It some cases properties of the elements were not same as defined by octave.

– Worked well only with lighter elements.

Mendeleev's periodic law :– The properties of elements are the periodic function

of their atomic mass.

Mendeleev's periodic table based on the chemical properties of elements.

Contain eight vertical columns called groups and seven horizontal rows called periods

form Mendeleev’s peridic table.

Achievements of Mendeleev’s Periodic table

– Elements with similar properties could be grouped together

– Some gaps were left for the undiscovered elements.

– Noble gases could be placed without disturbing the existing order.

Limitations:

– No fixed position for hydrogen

– No place for isotopes

– No regular trend in atomic mass.

Modern Periodic Table

Modern Periodic Law : Properties of elements are a periodic function of their

atomic number.

– Atomic Number – denoted by Z and equals to the no. of protons in the

nucleus of an atom.

– Modern periodic table contains 18 vertical columns known as groups and 7

horizontal rows known as periods.

– Elements in a group have valence electrons – No. of the shells increases as we go down the group.

– Elements in a period have same number of shells.

– Each period marks a new electronic shell getting filled.

– No. of elements placed in a particular period depends upon the fact that how

electrons are filled into various shells.


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– Maximum no. of electrons that can be accomodated in a shell depend on theformula 2n2 where n is the no. of the given shell.

eg. k shell – 2 x (1)2 = 2 elements in the first period L shell – 2 x (2) 2 = 8

elements in the second period.

– Position of the element in the periodic table tells about its reactivity.

Trends in the Modern Periodic Table

– Valency : No. of valence electrons present in the outermost shells.

– Atomic Size : Atomic size refers to radius of an atom.

– Atomic size or radius decreases in moving from left to right along a period

due to increase in nuclear charge

– Atomic size increases down the group because new shells are being added

as we go down the group.

Metallic Character : Metallic character means the tendency of an atom to lose

electrons.

– Metallic character decreases across a period because the effective nuclear

charge increases that means the tendency to lose electrons decreases.

– Metals are electropositive as they tend to lose electrons while forming bonds.

– Metallic character increases as we go down a group as the effective nuclear

charge is decreasing. Non metals are electronegative. They tend to form

bonds by gaining electrons.

– Metals are found on the left side of the period table while non-metals are

towards the right hand side of the periodic table.

– In the middle we have semi-metals or metalloid because they exhibit some

properties of both metals and non metals.

– Oxides of metals are basic in nature while oxides of non-metals are acidic in

nature.

(Refer the table given on side page)


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Gradation in Periodic Properties

S. Property Variation Reason Variation Reason

No. across period along group

1. Atomic size Decreases Due to increase Increases due to addition

in nuclear charge of new shells.

due to increase in

distance between

outer most electron

and nucleus.

2. Metallic Decreases due to increase Inc reases due to decrease in

Character in effective effective nuclear

nuclear charge charge tendency to

tendency to lose lose valence electrons

valence electrons increases.

decreases.

3. Non-Metallic Increases due to increase Decreases due to decrease in

Character in effective effective nuclear

nuclear charge charge tendency to

tendency to gain gain electron

electrons increases decreases


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EXERCISE

(Question Bank)

Very Short Answer type Questions. (1 mark)

1. Write down three elements which represent Dobereiner’s triad.

2. Write down two drawbacks of Newland’s law of octaves.

3. Which important property did Mendeleev used to classify the elements in his

periodic table.

4. Explain why the number of elements in the third period is 8?

5. Name the most metallic and most non-metallic element in the periodic table.

6. Define Isotopes.

7. What was the need for classification of elements?

8. Name two elements that have two electrons in their outermost shell.

9. How many vertical columns and horizontal rows are there in modern periodic

table. What is the special name assigned to them?

10. Name the element having electronic configuration 2, 8, 2.

Short Answer type Questions (2 Marks)

1. Why He, Ne and Ar are called inert gases?

2. Which one has greater atomic size – Cl or Br?

3. What were the drawbacks of Mendeleev’s periodic table? Write any two.

4. How does the tendency to lose electrons will change in a group and why?

5. Justify the statement – Atomic size of an element decreases along a period

whereas increasing down the group.

6. Why metallic oxides are basic in nature whereas Non-metallic oxides are

acidic in nature.


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Long Answer Type (3 Marks)

1. How do we calculate the valency of an element from its electronic configuration?

– How does the valency vary in a period?

– How does the valency vary in going down a group?

2. Study the variation in the atomic radii of elements given below and arrange

them in an increasing order

Na Li Rb Cs K

186 152 246 262 231

ii) Name the element which has the smallest and the largest atoms.

iii) How does the atomic size vary as we go down a group.

3. Four elements ABCD along with their electronic configurations are given

below

Elements – A B C D

Electronic Configuration – 2, 1 2, 8 2, 8, 1 2, 8, 8

4. Now answer the following questions

a) Which two elements belong to the same period,

b) Which two elements belong to the same group

c) Which element out of A and C is more reactive and why?

Long Answer Type Question (5 Marks)

1. Write down five major differences between Mendeleev periodic table andmodern periodic table.

2. Examine elements of the third period and classify them as metals and non

metals.

ii) On which side of the table do you find metals and why.

iii) On which side of the table do you find the non-metals and why?


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CHAPTER – 6

LIFE PROCESSES

All living things perform certain life processes like growth, excretion, respiration,

circulation etc.

All the processes like respiration, digestion, which together keep the living organisms

alive and perform the job of body maintenance are called life processes.

Examples :

Kinds of nutrition in which in organic

materials like CO2, water etc are utilized to

prepare organic food by the process of

pho tosynthe ses

Eg. Green Plants

Kinds of nutrition in which in organisms do

not possess the ability to synthesize their

own food. They depend on autotrophs for

their food supply directly or indirectly.

eg. Animals, Fungi


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Autotrophic Nutrition :

The organisms which carry out autotrophic nutrition are called autotrophs (green

plants)

Autotrophic nutrition is fulfilled by the process by which autotrophs take in CO2 and

H2O and convert these into carlohydrates in the presence of chlorophyll, sunlight is

called PHOTOSYNTHESIS

Equation :

Raw Materials for Photosynthesis :

Sunlight

Chlorophyl Sunlight absorbed by chlorophyll

CO2 enters through Stomata, and Oxygen (O

2) is released as by product

through stomata on leaf.

Water water + dissolved minerals like Nitrogen phosphorous etc are taken

up by the roots from the soil.

Site of Photosynthesis :

Chloroplast in the leaf. Chloroplast contain chlorophyll. (green pigment)

Main Events of Photosynthesis :

Absorption of light energy by chlorophyll

Conversion of light energy into chemical energy + splitting (breaking) of water

into hydrogen and oxygen. Reduction of CO

2 to carbohydrates.

STOMATA : Tiny pores present on the surface of the leaves

FUNCTIONS :

(i) Exchange of gases O2/CO

2

(ii) Loses large amount of water [water vapour] during transpiration.


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How do organisms obtain their food

Unicellular / single celled organism : food is taken up through entire surface.

Example : (i) Amoeba. (ii) Paramaecium


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NUTRITION IN HUMAN BEINGS

The human digestive system comprises of alimentary canal and associated disgestive

glands.

Mouth Intake of whole food

Teeth Chewing/grinding of food.

Tongue Rolling of food

+

Tasting of food+

Swallowing / pushing down of the food

Salivary Glands Secrete Saliva + Mucus.

Starch →Salivary

amylase

[Saliva]Sugar

Oesophagus Taking food from mouth to stomach by

Peristaltic movements

[contraction and expansion of muscles of the oesophagus]

Stomach Gastric glands secrete Gastric juice


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Small Intestinal

Small Intestine Villi → helps in absorption of food into the blood.

[finger like projections]

small intestine Receives

secretion from

Emulsification : The process of breakdown of large fatglobules into smaller fat globules by bile juice.

Large intestine Absorb excess of water.

The rest of the material is removed from the body via the

anus. (Egestion)


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Respiration

Respiration involves

(i) Gaseous exchange : Intake of oxygen from the atmosphere and release of

CO2 →

Breathing

(ii) Breakdown of simple food in order to release energy inside the cell →Cellular

Respiration

Breakdown of Glucose by various pathways

* Takes place in the presence of

oxygen

* Occurs in mitochondria

* End products are CO2

and H2O

* More amount of energy is released

* Takes place in the absence of

oxygen

* Occurs in cytoplasm

* End products are alcohol or lactic

acid.

* Less amount of energy is released.


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Human Respiratory System

Passage of air through the respiratory system.

Nostril

Nasal Passage

Nasal Cavity

Pharynx

Larynx

Trachea

Bronchi

Lungs

Bronchioles

Alveolar → Blood capillaries

* During inhalation the thoracic

cavity (chest cavity) expands

* Ribs lift up

* Diaphragm become flat in shape

* Volume of lungs increases and air

enters the lungs

* Thoracic cavity contracts

* Ribs move downwards

Diaphragm becomes dome shaped

* Volume of lungs decreases and air

exits from the lungs.


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Exchange of Gases between alveolus, blood and tissues.

Terrestial Organism – use atmospheric oxygen for respiration

Aquatic Organisms – used dissolved oxygen for respiration

Respiration in Plants :

Respiration in plants is simpler than the respiration in animals. Gaseous exchange

occur through

1. Stomata in leaves

2. Lenticels in stems

3. General surface of the roots.


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X-Science

The circulatory system in human beings consists of :

A Pumping OrganHeart

Blood vessels- Arteries & Veins

A circulatory mediumBlood & Lymph

Life Process (II)

Transporation and Excretion

– Human beings like other multicellular organism need regular supply of food,

oxygen etc., This function is performed by circulatory system or Transport

system.

– The circulatory system in human beings consists of :

DeoxygenateBlood

(from body)

VenaCava

RightAtrium

(Relaxed)

RightAtrium

(contracts)

RightVentricle(relaxed)

Body Parts

via AoRTA

Rightventricle

contracts

Lungs

Blood Circulation

in Human Heart

LeftVentricle

(contracts)

LeftVentricle(relaxed)

LeftAtrium

(contracts)

LeftAtrium

(relaxed)

Oxygenated blood

AORTA

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Blood(A fluid Connective Tissue)

Solid ComponentBlood Corpuscles

Liquid ComponentPLASMA

R.B.C.s BloodPlatelets

W.B.C.A yellow colour fluidcontain 90% water &10% Organic substanceslike

- Plasma Proteins viz.albumin, globulininorganic-mineral ions

Provide Bodydefence byengulfing thegerm cells & producingantibodies

helps inBloodClotting

- carries respectgas (O , CO )2 2- contain Hbimpart red colour to me blood

- Lymph - a yellowish fluids escapes from the blood capillaries into theintercellular spaces contain less proteins than blood. Lymph flows from thetissues to the heart assisting in transportation and destroying germs.

Blood Vessels

Arteries Veins1. Carry Oxygenated blood from

heart to body part except pulmonary Artery

2. Also called distributing Vessel

3. Thick and elastic

1. Carry deoxygenated bloodfrom body parts to heartexcept pulmonary vein.

2. Also called collecting Vessel.

3. Thin and Less elastic.

Transportation in Plants

Xylem Phloem

1. Carries water & mineralsfrom the roots to other partof the plant

2. No energy is used.

1. C a r r i e s p r o d u c t o f photosynthesis from leavesto the other part of the plant.

2. Energy is used from ATP

- There are two main conducting Pathways in a Plant

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– Transpiration is the process of loss of water as vapour from aerial parts of the plant.

Function :

1. Absorption and upward movement of water and minerals by creatingPULL.

2. helps in temperature regulation in Plant.

– Transport of food from leaves (food factory) to different part of the plant iscalled Translocation.

EXCRETION

– The process of the removal of the harmful metabolic wastes from the body.

– Excretory system of human beings includes :

1) A pair of kidneys

ii) A Urinary Bladder

iii) A pair of Ureter

iv) A Urethera

– Urine produced in the kidneys passes through the ureters into the urinary bladder where it is stored until it is released through the urethera.

– The purpose of making urine is to filter out waste product from the blood ie,urea which is produced in the liver.

– Each kidney has large numbers of filtration units called nephrons.

– The Urine formation involves three steps

1. Glomerular Filtration : Nitrogenous wastes, glucose water, amino acidfilter from the blood into Bowman Capsule of the nephron.

2. Tubular reabsorption : Now, useful substances from the filtrate arereabsorbed back by capillaries surrounding the nephron.

3. Secretion Extra, water, salts are secreted into the tubule which open upinto the collecting duct & then into the ureter.

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– Haemodialysis : The process of purifying blood by an artificial kidney. it ismeant for Kidney failure patient.

Excretion in Plants

– Oxygen, CO & H O2 2

– Other wastes may be stored in leaves, bark etc. which fall off from the plant.

– Plants excrete some waste into the soil around them.

– Gums, Resin In old Xylem

– Some metabolic wastes in the form of crystals of Calcium oxalates in theleaves of colocasia and stem of Zamikand.

Through stomata(Transpiration)

Life Processes

EXERCISE

(Question Bank)

Very Short Answers (1 Mark)

1. State one difference between autotrophic and heterotrophic mode ofnutrition.

2. What will happen to a plant if the xylem is removed.

3. What is the role of saliva in the digestion of food?

4. Name the tissue that transports water and minerals in plants.

5. What is the role of acid in our stomach?

6. What is emulsification

7. Name the organelle in which photosynthesis occur.

8. Name the largest artery in the human body.9. Define transpiration

10. What are structural and functional unit of kidneys called.

Short Answers (2 Marks or 3 Marks)

1. How is small intestine designed to absorb digested food?

2. What are stomata? Draw a labelled diagram of stomata.

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3. Write the equation for the process of breakdown of glucose in a cell

i) in the presence of oxygen

ii) in the absence of oxygen.

4. Write the difference between inhalation and exhalation.

5. List the three events which occur during photo synthesis.

6. How does transpiration helps in upward transport of substances.

7. Describe the process of double circulation in human beings.

8. Write the functions of the components of blood.

Long Answers (5 Marks)

1. Explain the process of digestion of food in mouth stomach and smallintestine in human body. Draw a well labelled diagram.

2. Draw a diagram showing Human Respiratory system. Label the following parts

i) Larynx ii) Trachea

iii) Bronchus iv) Lungs

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CHAPTER – 7

Control and Coordination

Living organisms respond and react to various stimuli like heat, light, cold, touch, pressure etc. Plants and animals both respond to stimuli but in different manner.

Example : withdrawl of hand on touching a hot object.

Control and Coordination in Animals

It is brought about in all animals with the help of two main systems

a) Nervous System b) Endocrine System

Nervous System :

Functions

i) To receive the information from environment

ii) To receive the information from various

body parts. (Stimuli Response)

iii) To act accordingly through muscles and glands.Stimulus : Any change in environment or within that bring about the reaction eg:touching a hot plate.

Response : The reaction of our body to these changes. eg. withdrawal of our hand

How do we detect that we are touching a hot object?

Receptors : Are specialised tips of some nerve cells that detect the informationfrom the environment.

Receptorsare

Sense Organs

Inner Ear

Photo receptorsEyes

Skin OlfactoryReceptor (Nose)

GustatoryReceptor (Tongue)

Hearing/Balance ofthe body

VisualStimulus

PainTouchHeat

SmellDetection

TasteDetection

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Neuron : Structural and functional unit of nervous system.

I II III

Neuron (3 main parts)

Dendrite Cell bodyand Axon

Synapse

Information isacquired

Informationtravels as an

electrical impulse

Part whereelectrical signalis converted into

chemical messagefor onward transmission

to next neuron

by release of neurotransmitters

Nucleus

Dendrite

Axon

Nerveending

CellpodyStructure of neuronFig. 7.1 (a) P 115

Synapse : The point of contact between the terminal branches of axon of oneneuron with the dendrite of another neuron is called synapse.

Reflex Action

A quick, sudden, immediate response of the body to the certain stimuli thatinvolves Spinal cord. eg. (not brain) withdrawal of hand, knee jerk etc.

Reflex arc : The pathway through which impulses pass is called reflex arc.

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Stimulus

eg. Heat

RECEPTOR ORGAN(SKIN)

Sensory Nerves

Spinal Cord

Motor Nerves

Response

eg. Withdrawalof

Hand

EFFECTOR ORGAN

(MUSCLE)

Refer to diagram Fig 7.2 Reflex arc

Response

Responses are of three main types

Voluntary : Controlled by fore brain

eg. Talking, Writing

Involuntary : Controlled by mid and hind brain

eg. Heart beat, vomiting, regulation of heartbeat

Reflex action : controlled by spinal cord eg. Withdrawl of hand on touching a hot object.

Human Nervous System

Central NervousSystem

Peripheral NervousSystem

Autonomic NervousSystem

(CNS (PNS) (ANS)

Brain SpinalCord.

Cranial Nerves

Spinal Nerves

Sympathetic NervousSystem

ParaSympathetic

NervousSystemArise from

the brainArise fromSpinal Card

Fore Brain

Mid Brain

Hind Brain

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Human Brain

Human brain has three major parts or regions

a) Forebrain b) Mid Brain c) Hind Brain

FOREBRAIN

Most complex/specialized part of the brain is CEREBRUM

FUNCTIONS :

1. Thinking part of the brain

2. Control the voluntary actions.

3. Store information (Memory)4. Centre associated withHUNGER

5. Receives sensory impulses from various body parts and integrates it

Mid Brain :

HYPOTHALAMUS : Chemical co-ordination

PITUITARY GLAND : Secretes hormones

Hind Brain :

CEREBELLUM i) Controls posture and balanceii) Control precision of voluntary actions

MEDULLA Controls involuntary actionseg. blood pressure, salivation, vomiting

PONS Involuntary action, regulation of respiration

Fig 7.3 Human Brain

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PROTECTION OF BRAIN AND SPINAL CORD

Brain : Brain is protected by a fluid filled balloon which acts as shockabsorber and enclosed in cranium (Brain Box)

Spinal Cord : Spinal Cord is enclosed in Vertebral column.

Coordination between Nervous and Muscular Tissue

Information[collected by

Nervous tissue](Sensory Nerve)

Central NervousSystem[CNS]

InformationProcessed

by[CNS]

Decesionmade

[by CNS]

(Motor Nerves)Message

Passed tomuscles

Muscles[Change in shapeand arrangement

of proteins]

Contraction[Muscle cell]

Muscle shorten

Action

Coordination in Plants

Movement dependenton growth

Movement independentof growth

[immediate responseto stimulus]

eg. dropping of leavesof Touch-me-not

plant on touching it

Movement in Plants

Tropic movements[directional movementsin response to stimulus]

Phototropism

Movementtowards light

Geotropism

Movementtowards gravity

Chemotropism

Movementtowards Chemicals/

growth of pollentube towards avule

Hydrotropism

Movementtowards /

water

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Plant hormones :

Are chemical compounds which help to coordinate growth, development andresponses to the environment.

Plant hormones : Main plant hormones are :

a) Auxin : [Synthesized at shoot tip]

Function : – Helps in growth

Phototropism : more growth of cells towards light.

b) Gibberellin : Helps in the growth of the stem

c) Cytokinins : Promotes cell division

d) Abscisic acid : Inhibits growth, cause witting of leaves.(Stress hormone)

Hormones in Animals

Hormones : These are the chemical messengers secreted in very small amounts byspecialised tissues called ductless glands. They act on target tissues/organs usuallyaway from their source.

Endocrine System helps in control and coordination through chemical compoundscalled HORMONES

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S.No.

Hormone EndocrineGland

Location Functions

1. Thyroxine Thyroid Neck/ Regulation of metabolismThroat of carbohydrates, fatsregion and proteins.

2. Growth Pituitary Mid Regulates growth andhormone development.

3. Adrenaline Adrenal Above Regulation (increasing) both of blood pressure, heartkidneys heat, carbohydrate

metabolism (duringemergency)

4. Testosterone Testes Genital/ Changes associatedSEX in Males lower with pubertyHormone abdomen (Sexual maturity)

estrogen Ovaries area

5. Insulin Pancreas Below Reduces and regulatesstomach blood sugar level

GO NADS

IODISED SALT IS NECESSARY BECAUSE :

Iodine mineral is essential part of thyronine hormone so it is important that wemust consume iodised salt as in turn it is essential for thyroid gland as it controlscarbohydrate, proteins and fat metabolism for best balance of growth deficiency ofiodine might cause disease called goitre

Diabetes :

Cause : It is due to deficiency of Insulin hormone secreted by Pancreas that is

responsible to lower/control the blood sugar levels.Treatment : Patients have to internally administer injections of insulin hormone

which helps in regulating blood-sugar level.

Feedback Mechanism

makes sure that hormones should be secreted in precise quantities and at right

time, which is regulated by feedback mechanism.

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Sugar level in the blood rises

Detected by cells of Pancreas

Synthesis insulin

Blood sugar level falls

Stop secreting moreinsulin

(like a float in watertank) S W I T C H O F F

F e e d b a c k s e n t

EXERCISE

(Question Bank)

Very Short Answers (1 Mark)

1. Where is auxin synthesized in plants?

2. Which gland is known as Master gland?

3. Name the hormone that regulates blood sugar level.

4. What is synapse.

5. What are tropic movements? Give one examples6. Define hormones

7. Which hormone has inhibiting effect on growth of plants

8. What is phototropism?

9. What are the components of central Nervous System.

10. What happens at synapse between two neurons.

Short Answers (2 Marks)

1. Draw diagram of neuron and label cell body, dendrites and axon.

2. What is reflex arc? Explain with the help of a flow-chart.3. Mention one function of each of the following

i) Cerebellum

ii) Pons.

4. What is the cause of diabetes? How it can be controlled.

5. Why it is advisable to use iodised salt.

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6. What are the different receptors present in our body? What are theirfunctions.

7. What are plant hormones? Name a plant hormone that promotes growth in plants.

8. What are sensory and motor neurons? Write their functions.

Long Answers (5 Marks)

1. What are hormones (in animals) List four characteristics of hormones. Namethe hormone required for the following.

i) Development of moustache and beard in human male

ii) Lowering of blood glucose.

2. Mention the functions of

a) Fore brain

b) Mid brain

c) Hind brain

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– Reproduction is the process by which living organisms produce newindividuals similar to themselves.

– Reproduction ensured continuity of life on earth.

– Reproduction - A bridge to hereditary transmission.

– It involves continuation of characters from the parents to daughter cells byCopying of DNA (Deoxyribose Nucleic Acid) molecules present in thechromosomes of the cell.

– Copying of DNAs is also not a foolproof exercise, even minute changes bringabout Variation in the blue print of the offsprings.

– The useful variations are retained while the harmful one does not go beyond.

– Actually variations help the species to withstand drastic environmentalchanges, thus save the species from becoming extinct and promotes itssurvival for a longer time.

– This inbuilt tendency of variation is the "fuel" for Evolution.

CHAPTER – 8

How do Organisms Reproduce

REPRODUCTION

Asexual Reproduction Sexual Reproduction

1. A single parent is involved

2. Gametes not formed

3. Progeny is Identical to parent

eg. Fission in Amoeba

1. Both Parents involved

2. Gametes are formed

3. Progeny is only geneticallysimilar to the parent.

– Asexual Reproduction is extremely useful as a mean of rapid multiplication.It is common in lower plants and animals.

– Different form of Asexual Reproduction.

1. FISSION : the parent cell divides/splits into two daughter cell-BinaryFission; splits into many cells-multiple Fission

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2. BUDDING : A new organism is produced as an outgrowth of the parent body part.

3. Spore Formation : Spores aresmall, bulb like structure develops

at the top of the erect hyphae of thefungus plant, released into the airan d g e rmin a te , i n to n ewindividuals after landing into foodor soil.

4. FRAGMENTATION : It is the accidental process when the broken pieces

of an organism (fragments) grows into a complete organism.

eg. fragmentation in

spirogyra

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5. REGENERATION : When the simple animals like Hydra Planariadevelop a new individual from their broken older part it is known asregeneration. It is carried out by specialised cells which grow large numbersof cells.

VEGETATIVE PROPAGATION :

A mode of reproduction in which part like the stem, root, leaves develop into new plant under favourable conditions.

Benefits1. Plants can bear flowers, fruits earlier than those produced from seeds.

2. Growing Banana, orange, rose, jasmine that have lost the capacity to produceseeds.

3. Genetical similarity is maintained in the plants.

eg. Sugarcane, rose, grapes by layering or grafting.

SEXUAL REPRODUCTION

When reproduction takes place as a result of fusion between two gamets, one fromeach parent, it is called sexual reproduction.

– This process of fusion between two gamets is called fertilization.

– The formation of gamets involves exchange of chromosomal (genetic)fragments between homologous chromosomes causing geneticrecombination which leads to variation.

SEXUAL REPRODUCTION IN PLANTS

It occurs mostly in flowering plants. In fact flowers are the reproductive organ of plants.

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FLOWERS

Bisexual Flowers Unisexual Flowers

Both male and female

Science 10 English

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