Water of Crystallization

Q.

What are the factors affecting the solubility of solute in solvent?

Q.

Crystals of a substance change their colour on heating but regain it after sometime, when they cooldown .

a) name one such substance.

b) explain the phenomena involved.

Q.

Water turns anhydrous copper sulfate blue

1. True
2. False

Q.

Prachi took 50 mL of water in two beakers at room temperature and added sodium chloride to one beaker while sugar to the other, till no more solute would dissolve. Then she heated the contents of the beakers and added more solutes in them.
(a) Will the amount of salt and sugar that can be dissolved in water at given temperature same ?
(b) What will you expect to happen if she cools the contents of the beakers ? Justify your answer.

Q.

State whether the following statement is true or false :

Copper sulphate crystals are always wet due to the presence of water of crystallisation in them.

Q.

What do you understand by the water of crystallisation?

Give four substances which contain water of crystallisation and write their common names.

Q. What happens when crystals of washing soda are left open in dry air?what is this change named as?

Q.

Crystal of substance change the colour of heating is a closed vessel but regained it after sometime when they were allowed to cool down . explain the phenomenon involved

Q.

How will you purify a sample of impure sugar?

Q.

You are provided with a mixture of naphthalene and ammonium chloride by your teacher. Suggest an activity to separate them with a well-labelled diagram.

Q. Define the following terms:
(a) Efflorescence
(b) Hygroscopy
(c) Water of crystallisation.

Q.

Write the chemical formula of the chemical compounds that are abbreviated as MOM and POP.

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

Q. A metal nitrate $A$ on heating gives yellowish brown coloured metal oxide along with brown gas $B$ and colourless gas $C$.

Q. In which mode of expression, the concentration of a solution remains independent of temperature?
(IIT-JEE, 1988)

1. Formality
2. Molality
3. Molarity
4. Normality

Q.

Explain the methods required for the separation of the following mixtures.

iron filing, sand, and iodine

Q.

……. copper sulfate is used for testing water.

Q.

You are provided with a mixture containing iron filings, ammonium chloride, sand, and sodium chloride. How will you separate these substances from the mixture?

Q.

Distinguish between drying and dehydrating agent

Q.

What are emulsions? Give two examples?

Q. vi. What is meant by ̳Water of Crystallisation‘ of a substance? Describe an activity to
show that.

Q. Define:
(a) a pure substance
(b) sublimation
(c) loading
(d) separation of mixture

Q. In a solution, is present in more quantity and other substances are dissolved into it.

1. solute
2. solvent
3. mixture

Q. A molal solution is one that contains 1 mol of a solute in
(IIT-JEE, 1986)

1. 1000 g of solvent
2. 1 L of solvent
3. 1 L of solution
4. 22.4 L of solution

Q. Are the crystals of salts really dry

Q.

Match the given compounds with their chemical formulas.

Column A	Column B
Blue vitriol	${\text{Na}}_{2}C{O}_3.10H_{2}O$
Washing soda	${\text{CaSO}}_4.2H_{2}O$
Plaster of Paris	${\text{CaSO}}_4.5H_{2}O$
Gypsum	${\text{CaSO}}_4.½H_{2}O$

Q. What do you understand by water of crystallization ?
Give four substances which contain water of crystallization and write their common names.

Q. The colour of the salt formed due to the removal of water crystals from hydrated copper sulphate upon heating is _________.

1. green
2. red
3. orange
4. white

Q. Sodium carbonate can be tested on: (i.e. shows any observable changes)

1. Copper sulphate
2. Ammonium sulphide
3. Ferrous chloride
4. Potassium Iodide

Q.

Which of the following formulas are correct?

1. Gypsum - CaSO${}_4$.2H${}_2$O

2. White vitriol - ZnSO${}_4$.5H${}_2$O

3. Plaster of Paris - CaSO${}_4$.1/2 H${}_2$O

4. Blue vitriol - CuSO${}_4$.5H${}_2$O