Question

a)What is a chemical reaction?
b)State the conditions necessary for a chemical change or reaction.

Answer 1

a) A chemical reaction is a process that occurs when two or more molecules interact/transform to form new product(s).
Example: $\mathrm{HCl}\left(\mathrm{aq}\right)+\mathrm{NaOH}\left(\mathrm{aq}\right)\to \mathrm{NaCl}\left(s\right)+H_{2}O\left(l\right)$

b) The conditions necessary for chemical change or reaction are:

• The reactants must be in closed contact.
• The physical state of reactants should be the same in case of some chemical reaction.
• The presence of a sufficient amount of energy in the form of heat, and light.
• The suitable temperature and pressure.
• The presence of a catalyst.