Plaster of Paris

Q.

The Plaster of Paris should be stored in a moisture-proof container. Explain why?

Q.

How is plaster of Paris is prepared? What is its chemical formula and chemical name?

Q.

How does Plaster of Paris help in repairing fractured bones?

Q.

Give reasons for the following:

Only one-half of the water molecule is shown in the formula of Plaster of Paris.

Q.

Plaster of Paris hardens by

1. Giving off ${\mathrm{CO}}_2$

2. Changing into ${\mathrm{CaCO}}_3$

3. Giving out water

4. Utilizing water

Q.

Plaster of Paris (POP) is formed by heating gypsum.

1. True
2. False

Q.

Write the chemical equation for the reaction when water is added to plaster of Paris.

Q.

Why are casts made from Plaster of Paris sharp?

Q. Hydrated copper sulphate contains how many molecules of water of crystallisation?

1. Four
2. Five
3. Six
4. Seven

Q.

A compound which is prepared from gypsum has the property of hardening when mixed with proper quantity of water. Identify the compound. Write the chemical equation to prepare the compound. Mention one important use of the compound.

Q.

211(a). Why is the formula of plaster of Paris written as ${\mathrm{CaSO}}_4.\frac{1}{2}{\mathrm{H}}_2\mathrm{O}$? How is it possible to have half a water molecule attached to${\mathrm{CaSO}}_4$?

Q. Gypsum is a widely occurring mineral. It is the sulphate of calcium with two molecules of water attached. On heating it loses three-quarters of its water and becomes:

1. baking soda
2. plaster of Paris
3. a pearl
4. an ultramarine

Q.

A compound called gypsum has the property of hardening when mixed with proper quantity of water. Identify the compound. Write the chemical equation of its preparation. Mention one important use of the compound.