2nd Unit Test X Class P.S. ( Chemical Equations )

Section-1

Answer all questions 5x1=5m

1). Fill in the boxes to complete the representation of a chemical equation

2). Why should a chemical equation be balanced ?

3) Complete the following Precipitation reaction

Potassium iodide + Silver nitrate → ------------------------------- + ---------------------------

4).Mention any two changes that occur in a chemical reaction.

5). Give two examples of chemical reactions in our daily life.

Section-2

Answer any three questions 3x2=6m

6). A substance ‘ X’, when mixed with water is used for whitewashing . The substance’ X ‘ is formed when a substance’ Y ‘decomposes. Identify X & Y and write their chemical formulae.

7).Balance the equations : (i) NO2 + H2O → HNO3 (ii) CaCO3 + HNO3 → Ca(NO3)2 + H2O + CO2

8).Ramu of 10th class balanced a chemical equation like this : 2 C3H8 + 10 O2 → 6 CO2 + 8 H2O and showed it to his teacher. While correcting, the teacher reminded Ramu of a rule to be kept in mind to balance an equation.

(i) What is the rule, which the teacher thought, Ramu forgot ?

(ii) What is the correct form of the above balanced equation, if you think Ramu did wrong?

9) Answer the questions with the help of the given equation

(i) What type of reaction is this ?

(ii) What does X stand for ?

(iii) What does Y stand for ?

Section-4

Answer any one question 1x4=4m

10) With the help of an activity,show that Iron is more reactive than Copper.

11) Some iron nails are dropped in four test tubes A,B,C,D. The other conditions are shown in the diagrams .Explain in which test tube the nails get rusted basing on the available conditions.

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Answer all questions 20 x ½ = 10

Multiple choice questions

1) N2 + H2 → NH3 .The mole ratio of reactants and products in this equation is…. --------

A) 1 : 1 : 1 B) 1 : 2 : 3 C) 1 : 3: 2 D) 3: 2 : 1

2) The life process which is endothermic….. --------

A) Digestion B) Excretion C) Photosynthesis D) Respiration

3) corrosion of ---------- is a more serious problem ---------

A) Copper B) Silver C) Gold D) Iron

4) What property stays the same both in physical and chemical changes ----------

A) Density B) Shape C) Mass D) Arrangement of particles

5) Which of the following is not a balanced equation ----------

A) Mg + CuSO4 → MgSO4 + Cu B) Zn + S → ZnS

C) Fe + Cl2 → FeCl3 D) NaOH + HCl → NaCl + H2O

Fill in the blanks

6) The browning of cut surface of apple is due to ----------------------

7) Temporary changes are called --------------------------------------

8) How many grams of Hydrogen make one mole of H2 ----------------------

9) ----- Na + O2 → 2 Na2O . The missing number in the equation is ------------

10) The change which can not be reversed is ---------------------------

Test Tube A B C D

Rust / No rust

Reason

---- available

----not available

11) X + YZ → XY + Z. This is an example for --------------------------------------- reaction.

12) Dissolving of sugar in water is an example of --------------------------------

13) 2S + 3O2 → 2SO .Find the right subscript in the placeof

14 ) In a chemical equation → shows ------------------------------ of the equation.

15 Rancidity of food material is due to oxidation of -------------------------------- present in it.

Match the following

16) Water ( ) a) CaO

17) Quick lime ( ) b) Ag2S

18) Propane ( ) c) H2O

19) Glucose ( ) d) C3H8

20 Silver Sulphide ( ) e) C6H12O6

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