chemical equation and reaction

TRANSITION {Striving singularity, Exploring Excellence} m

CHEMICAL EQUATION AND REACTIONS

Time: 2½ Hours                                                                                                    Max. Marks: 60

General Instructions

1. The question paper comprises of two sections A and B. You have to attempt both the sections.

2. All questions are compulsory.

3. There is no overall choice. However, internal choice has been provided in all the three questions of five marks category. Only one option in such questions is to be attempted.

4. All questions of section A and all questions of section B to be attempted separately.

5. Questions 1 to 6 in section A and 19 to 21 in section B are very short answer type questions and carry one mark each.

6. Questions 7 to 12 in section A and 22 to 24 in section B are short answer type questions and carry two marks each.

7. Questions 13 to 16 in section A and 25 and 26 in section B are also short answer type questions and carry three marks each.

8. Questions 17 and 18 in section A and question 27 in section B are long answer type questions and carry five marks each.

1.      T

2.      T

3.      T

4.      T

5.      State and give example for the double displacement reaction.

6.      T

7.      Magnesium ribbon burns with a dazzling flame in air (oxygen) and changes into a white substance, magnesium oxide.

a.       Is magnesium ribbon being oxidized or reduced in this reaction?

b.       Why should magnesium ribbon be cleaned before burning in air.

8.      A solution of a substance ‘X’ is used in white washing.

a.       Name the substance ‘X’ and write its formula.

b.      Write the reaction of the substance ‘X’ named in ‘a’ with water. Which type of reaction is this?

9.      Why does the colour of copper sulphate solution change when an iron nail is dipped in it ?

10.  What is a balanced chemical equation? Why chemical equations should be balanced.

11.  T

12.  T

13.  T

14.  T

15.  Differentiate between exothermic and endothermic reaction with examples.

16.  Why is decomposition reaction called as opposite of combination reaction.

17.  Why is respiration considered as an exothermic reaction.

18.  What is the difference between displacement and double displacement reaction.

19.  What do you mean by precipitation reaction? Explain giving examples.

20.