Science 10

Chemistry is the study of matter, its properties and its changes of

transformations

Classifying Matter

MATTER

PURE SUBSTANCES

MIXTURES

SOLUTIONS COLLOIDSMECHANICAL

MIXTURESELEMENTS COMPOUNDS

Are the particles identical?

Y N

TyndallEffect?

Y N

Are the atomsIdentical?

Properties of matter

Characteristicsof Matter

PhysicalNo New Substance

Created

ChemicalNew substance(s)

created

Qualitative(ie: methane is a

Clear gas)

Quantitative(ie: 10 L methaneweighs 18.5 g

Qualitative(ie: Colour change,

Precipitate…)

Quantitative(ie 2g H2O

Makes 1 g H2 + 1 g O2

Using Chemical PropertiesTests for gases

Property Observation Explain

O2 Oxidizing agentReignites a

smoldering splint

O2 rich environment allows faster

burning

CO2 Non-flammablePuts out a flaming

splint

CO2 displaces the O2 that is allowing

the flame

CO2Reacts with limewater

Turns cloudy in limewater

Forms an insoluble, white precipitate

H2

Combustible / explosive if under

pressure

Rapidly ignites when flame approaches

the tube

H2 mixes and reacts with the O2 that is in the tube

HHPS - WHMISThe WHMIS and HHPS safety labeling systems are based on the chemical and physical properties of all substances deemed hazardousat home (HHPS) and in the workplace (WHMIS).

Elements and the Periodic TableThe structure of the periodic table is designed to help us explain and predict the physical and chemical properties, and atomic structure of each of the elements.

Periods :(rows)# of shells

Families (columns):Similar PropertiesSame ionic charge

Predicting The Reactivity Of Elements(based on valance and # of shells)

metals

More reactive

Down and

Left on table up and righton the table

More reactive

non-metals

Atomic ModelingThe Bohr-Rutherford models shows negatively charged electrons in orbitsaround a nucleus of positive protons and negative neutrons.

24 – atomic Mass (P + N)

Mg 12 – atomic number (P = E)

12 - N

12 P+

12 No

2 e- 8 e- 2 e-

Lewis Dot Diagrams show the symbol surrounded by the electrons (represented by dots) in its valance shell

oxygen with its 6 valance electrons the molecular compound ethane

Elements into Compounds

Ionic CompoundsWhen a metals combine with

non-metals they form an ionic

bond between them. These

compounds are soluble in water

since the charged ions can

disassociated.

Ie Na + Cl Na+ Cl-

Molecular CompoundsWhen non-metals combine they do

not form ions. Instead electrons are

shared, creating covalent bonds

between them. These form molecules

that do not disassociate and will only

be soluble if polar

Ie: 2 H + O H2O

Atoms seek to become stable (full octet) by losing or gaining electronin their outer shell (valance shell). Sometimes they stabilize by forming ions, others they seek out others to share electrons and stabilize together.

Nomenclature - Ionic CompoundsIonic compounds form between a positive metallic ions and negative non-metallic ions, but the completed ionic compound is neutral. So…The total charges on each side of the molecule must be equal.

ie: using lewis dot diagrams for calcium and iodine

Name of formula (non-metal – “ide”) So… Calcium Iodide

. . . . . . . .

Ca + : I : : I : [Ca]+2 + [ : I : ] - [ : I : ] -

. . . . . . . .

Chemical formula CaI2Here two iodine atoms are necessary to accept the two electrons offered by calcium. In accepting the electrons each iodine becomes negatively charged and the calcium becomes a +2 ion upon losing its two electrons…Both sides of the formula have a total of 2 opposite charges neutral

Nomenclature: More Than One ChargeSome elements, like copper (Cu+, Cu+2) and lead (Pb+2, Pb+4), form more than one kind of ion. Use UPC or Stock systems when naming ionsof metals that have more than one ionic charge.

Compound formed between Fe+3 and O+2

Name: Iron (III) Oxide (or Ferric oxide)

Formula: Fe+3 + O+2 2 Fe+3 + 3 O+2

So… Fe2O3

Sometimes the Compound FeO is formed... What would it be called?

Since the oxygen ion has a charge of -2, the iron ion must have a charge of +2 to fulfill this 1:1 ratio.

So… Iron (II) Oxide (or Ferrous

Oxide)

Polyatomic CompoundsPolyatomic ions are groups of atoms that tend to stay together and carryoverall ionic charge.

Nitrate NO3- looks like this: O O

[ N ]-

O

Compound formed between Ammonium ion (NH4+) and Sulphate (SO4

-2)

Name: Ammonium Sulphate

Formula: 2 (NH4+) + SO4

-2 (NH4)2SO4

Here two polyatomic ions of ammonium are necessary to neutralize the 2 negative charges provided by the sulphate polyatomic ion.

When naming compounds and writing formula the same basic premise thatboth sides of the formula must have equal/opposite total charges is in effect.

Nomenclature: OxyacidsOxyanion

FormulaOxyanion

NameOxyacid

Formula

Oxyacid Name

NO3- nitrate HNO3 nitric acid

NO2- nitrite HNO2 nitrous acid

SO32- sulfite H2SO3 sulfurous acid

SO42- sulfate H2SO4 sulfuric acid

PO43- phosphat

eH3PO4 phosphoric acid

ClO3- chlorate HClO3 chloric acid

CO32- carbonate H2CO3 carbonic acid

Remember: H+ , ite always one less “O” than ate but same charge, and ate:ic, and ite:ous.

Molecular CompoundsDiatomic elements (HOFBrINCl)2 always form in pairs. The bonds that form between them are covalent.

Other molecular compounds that form covalent bonds use the following prefixes for the anion: mono, di, tri, tetra, pent(a).

Molecular Compounds: Hydrocarbons

Hydrocarbons are the simplest of the organic compounds. As the name suggests, hydrocarbons are made from hydrogen and carbon.

AlkanesThe alkanes are a family of hydrocarbons that share the same general formula. This is:  

CnH2n+2  Notice that double bonds can be formed with some of these

Synthetic SubstancesTiny molecules strung in long repeating chains form polymers. Why should you care? Well for one thing, your body is made of them. DNA, the genetic blueprint that defines people and other living things, is a polymer. So are the proteins and starches in the foods we eat, the wheels on our skateboards and in-line skates, and the tires on our bikes and cars. In fact, we’re surrounded by polymers every day, everywhere we go.

polyethylene

RNA formation

Glycogen – muscle sugarCopper-nanopolymers sandwich sticks like glue

Describing Chemical ReactionsThe Law of Conservation of Mass states, in a chemical reaction, the total mass of the reactants is always equal to the mass of the products.What goes into the reaction must come out (and vice versa)!

Ex: Water is broken down into hydrogen and oxygen when electrolyzed!

Word Equation water (l) oxygen (g) + hydrogen (g)

Skeleton Equation H2O H2 + O2

2(H = 2 O =1) 2(H = 2) 0 = 2

Balanced Equation 2 H2O 2 H2 + O2

Types of Reactions - CombustionA combustion reaction is a rapid chemical reaction of two or more substances (a fuel (e.g., wood, coal, oil, or natural gas) and an oxidizer) with a characteristic liberation of heat and light. (commonly called burning)

Incomplete combustion, when insufficient oxygen is available, can also causethe production of CO and C. Other impurities in the fuel can create by-products

Types of ReactionsCombination or synthesis                                 A  +  B AB

+

Decomposition                                                      AB   A  +  B

+

Substitution or Single Replacement            A  +  BC   B  +  AC

+ +

Metathesis or Double Displacement        AB  +  CD   AD  +  CB

+ +

Rates of reactionCollision Theory – the rate of reaction is affected by the number of (effective) collisions of reactant molecules.

What affects the number of collisions?

Concentration

Surface Area Catalyst (enzyme)

Temperature

AcidsAcids are sour tasting, water-soluble substances. They are consideredproton donors since the hydrogen ions that distinguishes them is displaced during the reaction.

Ions disassociated when dissolved in water HCl H+ + OH-

With metals, the H+ is displaced to form H2(g)

zinc + hydrochloric acid hydrogen + Zinc chloride

With carbonates, water and carbon dioxide are formed.

Hydrochloric acid + calcium carbonate calcium chloride + water + carbon dioxideCommon AcidsAcetic HC2H302(aq)

Citric acid HC6H7O7(aq)

Sulfuric acid H2SO4

Hydrochloric HCl

Making acids

non-metal oxide + water Acid

BasesBases are bitter-tasting, water-soluble substances that feel slippery to the touch. They are good conductors of electricity because theyrelease OH-, proton acceptors. Substances that are basic are describedas alkaline.

Common Bases

Draino: drain cleaner (sodium hydroxide – NaOH)breaks down protein in hear

Bleach: Sodium hypochlorite – NaClOBaking soda: Sodium bicarbonate – NaHCO3

Making acids

Metal Oxide + Water Base

The pH Scale The pH scale represents how acidic or basic a solution is. The pH scale is a logarithmic scale. Which means that one unit on the scale represents a Tenfold effect on the concentration of the solution.

pH is defined as pH = -log10[H+]

Therefore pH of 7 has 1.0 x 10-7 [H+] or 1.0 x 10-7

[OH-]pH of 1 has 1.0 x 10-1 [H+] or 1.0 x 10-13 [OH-]ph of 9 has 1.0 x 10-9 [H+] or 1.0 x 10-5 [OH-]

NeutralizationNeutralization: As you can see from the equations, acids release H+ into solution and bases release OH-. If we were to mix an acid and base together, the H+ ion would combine with the OH- ion to make the molecule H2O, or plain water:

H+(aq) +   OH-

(aq)          H2O

The neutralization reaction of an acid with a base will always produce water and a salt, as shown below:

Acid Base Water Salt

HCl  +  NaOH          H2O  +  NaCl

HBr  +  KOH          H2O  +  KBr

Common acid base reactions are: baking powder, plumbers use HCl, antacids, pool chemistry, hair products,