Sub. -– Chemistry
Attempt all questions :––
1. Fill in the blank (1×5=5)
(a) The chemical change involving iron and HCl illustrate a _______ reaction.
(b) In the type of reaction called ______ two compounds exchange their positive and negative radicals .
(c) A catalyst either _____ or _____ the rate of a chemical change but itself remains ____ at the end of the reaction.
(d) Formula of iron(3) carbonate is ________ .
(e) Symbolic expression for a molecule is called ______.
2. Complete and balance the following reactions :. ( 2×5=10)
(a) NaCl(aq) + AgNO3 (aq) ––-->
(b) Pb(NO3 )2 + KI ---–>
∆
(c) CuCO3 –------------>
(d) Pb(NO3)2 –----------->
Pt
(e) NH3 +O3 ––---------->
3. Define the following: (2×5=10)
(a) Photochemical reaction
(b) Electrochemical reaction
(c) Endothermic reaction
(d) Exothermic reaction
(e) Decomposition reaction
4. What do you understand by chemical.
reaction ? (3)
5.State the main characteristics of chemical
reactions . Give at least one example in
each case . (3)
6. What do you understand by hydrolysis ?
Explain giving examples . (3)
7. Find the percentage mass of water in the
Epsom salt MgSO4 . 7H2O . (3)
8. Explain the terms valency and variable
valency . (3)
