Question

3. Explain, giving one example for each of the following chemical changes:
(a) Double decomposition (b) Thermal dissociation
(c) Reversible reaction (d) Displacement

Answer 1

Answer:

(a)a reaction in which two compounds exchange ions, typically with precipitation of an insoluble product

eg. AgNO3 + NaCl → AgCl + NaNO3.

(b) The breaking down of a chemical compound by heat into smaller components which recombine to form the original compound on cooling

eg. 2H2O ⇄ 2H2 + O2, CaCO3 ⇄ CaO + CO2)

(c) A reversible reaction is a reaction in which the conversion of reactants to products and the conversion of products to reactants occur simultaneously

eg. reaction of hydrogen gas and iodine vapor to from hydrogen iodide.

Answer 2

Explanation:

displacement it is a chemical change in which a more active element displace a less active element from its salt solution

AB+C----- AC+B