Question

When zinc carbonate is heated and cooled, the change(s) that are observed are:

• A. physical
• B. nuclear changes
• C. first chemical and then physical
• D. first physical and then chemical

Answer 1

The correct option is C first chemical and then physical

When Zinc carbonate is heated which is a white powdery solid, gives carbon dioxide and a yellow solid of zinc oxide.

$ZnC{O}_3\to ZnO+C{O}_2\uparrow$

(yellow)

As it forms different products, it undergoes chemical changes.

On cooling yellow solid turns in to white, which is a physical change.

$ZnO⟶ZnO$

(yellow) (white)

The process involves both physical and chemical change. The heating of zinc carbonate is chemical change whereas cooling the product obtained is a physical change.

Hence, option $C$ is correct.