Question

One of the conditions necessary for a chemical reaction is _____________ (heat/air).

Answer 1

Chemical reactions

• When two or more substances chemically combines with each other and form a new substance with different properties are called chemical reactions.
• $\underset{\mathrm{Reactants}}{\mathrm{A}+\mathrm{B}}\to \underset{\mathrm{Products}}{\mathrm{C}+\mathrm{D}}$

A. Reactants

• Reactants are are the substances which combines to form different products.
• These are written on left side of chemical reaction.

B. Products

• Products are are the substances which is formed after a chemical reaction.
• These are written on right side of chemical reaction.
• For example,

$\underset{\mathrm{Nitrogen}}{{\mathrm{N}}_2\left(\mathrm{g}\right)}+\underset{\mathrm{Hydrogen}}{3{\mathrm{H}}_2\left(\mathrm{g}\right)}\underset{\mathrm{Pt}\left(\mathrm{platinum}\right)}{\overset{240\mathrm{atm}\mathrm{pressure}}{\to }}\underset{\mathrm{Ammonia}}{2{\mathrm{NH}}_3\left(\mathrm{g}\right)}$

Conditions necessary for a chemical reactions are -

1. Close contact - For a chemical reaction to occur, the reactants must be brought into close proximity, i.e. combined.
2. Solution form - Some compounds only react with each other when they are mixed in a solution form, such as alcohol and water.
3. Heat - To undergo a chemical transformation, some reactants must be heated.

For example, $\underset{\mathrm{Ferrous}\mathrm{Sulphate}}{{\mathrm{FeSO}}_4\left(\mathrm{s}\right)}\stackrel{\mathrm{Heat}}{\to }\underset{\mathrm{Ferric}\mathrm{oxide}}{{\mathrm{Fe}}_2{\mathrm{O}}_3\left(\mathrm{s}\right)}+\underset{\mathrm{Sulphur}\mathrm{dioxide}}{{\mathrm{SO}}_2\left(\mathrm{g}\right)}+\underset{\mathrm{Sulphur}\mathrm{trioxide}}{{\mathrm{SO}}_3\left(\mathrm{g}\right)}$

1. Light - In the presence of light, some reactions occur.

Hence, one of the conditions necessary for a chemical reaction is heat (heat/air).