Baljinder Kaur Solutions for Chapter: Physical and Chemical Changes, Exercise 2: Worksheet

Classify the following as physical or chemical change. Think of a reason in your mind.

Conversion of sulphur dioxide to sulphur trioxide

${\mathrm{H}}_2+{\mathrm{Cl}}_2\stackrel{\mathrm{Diffused} \mathrm{sunlight}}{\to }2\mathrm{HCl}$

The given reaction is:

$2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\stackrel{\mathrm{Electric} \mathrm{current}}{\to }2{\mathrm{H}}_2\left(\mathrm{g}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)$

The given reaction is:

Chemical reactions occur when substances are brought in _____ contact.

Iron and sulphur combine to form _____.

_____ is a catalyst to convert sulphur dioxide to sulphur trioxide.

_____ acts as a promoter during manufacture of ammonia.

If _____ (concentration of reactants/concentration of products) are more, the rate of reaction is more.