(a) What: is a chemical reaction?
(b) State the conditions necessary for a chemical change or reaction.
Give an example of each of the following chemical changes.
(a) A photochemical reaction involving
(i) silver salt (ii) water
(b) A reaction involving
(i) blue solution
(ii) formation of a dirty green precipitate
(c) Two gases combine to form a white solid.
(d) Two solids combine to form a liquid.
(e) A reaction where the color change is noticed.
When hydrogen burns in oxygen, water is formed; when electricity is passed through water, hydrogen
and oxygen are given out. Name the type of chemical changes involved in the two cases.
Explain, giving one example for each of the following chemical changes:
(a) Double decomposition (b) Thermal dissociation
(c) Reversible reaction (d) Displacement
Decomposition brought about by heat is known as thermal decomposition. What is the difference
between thermal dissociation and thermal decomposition
a. Which of the following is not a characteristic of a chemical change?
i. It is irreversible.
ii. No net energy change is involved.
iii. A new substance is formed.
iv. Involves absorption or liberation of energy.
b. A reaction of a type: AB + CD → AD + CD, involves
i. No chemical change
ii. Decomposition of AB and CD
iii. Exchange of ions of AB and CD
iv. Combination of AB and CD
c. The reaction BaCl2(aq) + H2SO4(aq) → BaSO4(s) + 2HCl(aq) is
i. Displacement reaction
ii. Neutralisation reaction
iii. Decomposition reaction
iv. Double displacement reaction
d. Thermal decomposition of sodium carbonate will produce
i. Carbon dioxide
iii. Sodium hydroxide
iv. No other product
Give an example of a reaction where the following are involved
(a) Evolution of heat
(b) Absorption of heat
(c) High pressure is required
Complete and balance the following reactions:
(a) NaCl(aq) + AgNO3(aq) →
(b) Pb(NO3)2 + KI →
(e) NH3 + O2----
What do you observe? When
a) Lead nitrate is heated.
b) Silver chloride is exposed to sunlight.
c) Hydrogen peroxide is exposed to sunlight.
d) H2S gas is passed through a copper sulphate solution.
e) Barium chloride is added to sodium sulphate solution
f) Water is added to the quick lime.
g) Sodium chloride solution is added to silver nitrate solution
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