CHEMISTRY (VIII) Weekly Test

Week -1   

               CHEMISTRY

(Language of Chemistry, Chemical Reaction)

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Question 1. (Any Three).       1x3= 3

Classify the following reactions

i) Zn(s) + H₂SO₄(aq)-->ZnSO₄+ H₂ (g)

ii) BaCl₂(aq)+ Na₂SO₄(aq) --> BaSO₄(s) + 2NaCl(aq)

iii) 2CO(g) + O₂(g) ---> 2CO₂(g)

Iv) 2KNO₃(s) ---> 2KNO₂(l)+ O₂(g)

Question 2 (Any Three)        2x3 = 6

Define:

i) Chemical double decomposition

ii) Catalyst

iii) Oxidising agent

iv) Inflammable substance 

Question 3.                                    (2)

CuO(s)+ H₂(g)--------Cu(s)+ H₂O(l).

In the above reaction, by giving reasons, explain which substance is:

i) Oxidised

ii) Reduced

iii) Oxidising agent

iv) Reducing agent

OR

Write the formula of the following:

i) Ammonium sulphate

ii) Zinc carbonate

iii) Lead hydroxide

iv) Barium chooride

Question 4.                                 (3x1)

State the valency and formula of the following:

i) Ammonia

ii) calcium

iii) Ferric

Question 5.                            1x3 = 3

Write the formula and then balance the following equations:

i) Ammonium chloride --> Ammonia+ Hydrogen chloride

ii) Red lead oxide --> lead monoxide+ Oxygen

iii) Sodium nitrate --> sodium nitrite+ Oxygen.

Question 6.                                     (1)

XCl₂ is the chloride of metal X. Write down the formula of sulphate and hydroxide.         

Question 7.                                    (2)

What is the difference between Exothermic and Endothermic reaction.