Chemistry
Answer
A chemical change is a permanent change in which the chemical composition of a substance is changed and one or more new substances with different chemical compositions and different properties are formed.
Examples :
Pb(NO3)2 (s) + 2KI (s) ⟶ 2KNO3 + PbI2 (s)
NaCl (aq.) + AgNO3 (aq.) ⟶ AgCl (white ppt.) ↓ + NaNO3 (aq.)
Related Questions
What do you understand by a 'chemical reaction'?
Give an example of each of the following chemical changes.
(a) A reaction involving
(i) change of state
(ii) formation of a precipitate
(b) An exothermic and an endothermic reaction involving carbon as one of the reactants.
(c) A reaction where colour change is noticed.
Define exothermic and endothermic reactions. Give two examples in each case.
Why is energy involved in a chemical change?