Sublimation

Q.

Why does solubility of gases increase with decrease in temperature?

Q. The process in which solids directly change into gases is known as _______________.

1. Evaporation
2. Crytallisation
3. Condensation
4. Sublimation

Q.

Naphthalene balls get smaller in size when kept exposed for a few days, due to sublimation.

1. True

2. False

Q.

Name the process associated with the following (a) Dry ice is kept at room temperature and at one atmospheric pressure. (b) A drop of ink placed on the surface of water contained in a glass spreads throughout the water. (c) A potassium permanganate crystal is in a beaker and water is poured into the beaker with stirring. (d) An acetone bottle is left open and the bottle becomes empty. (e) Milk is churned to separate cream from it. (f) Settling of sand when a mixture of sand and water is left undisturbed for some time. (g) Fine beam of light entering through a small hole in a dark room, illuminates the particles in its paths

Q.

A mixture of iodine and sand can be separated by the process of ___.

1. Distillation

2. Sublimation

3. Chromatography

4. Crystallisation

Q. If moth balls are kept at room temperature, then they undergo:

1. Boiling
2. Melting
3. Sublimation
4. Condensation

Q.

Naphthalene balls become smaller in size when kept exposed to air for a few days.

1. True

2. False

Q. Solid camphor converts to liquid on heating.

1. True
2. False

Q. Which among the following substances undergoes sublimation?

1. Iodine
2. Camphor
3. Ink
4. Naphthalene

Q.

When a mixture of common salt and ammonium chloride is heated it is observed that

1. solid common salt get deposited on the cooler part of the funnel while solid Ammonium Chloride remain in the China dish

2. the mixture of common salt and ammonium chloride turns into greased crystal when allowed to cool

3. The ammonium chloride gets deposited on the cooler part of the funnel and solid common salt remain in the China dish

4. The droplet containing both common salt and ammonium chloride appears on the upper part of the funnel while some molten mixture of common salt and ammonium chloride remains in the China dish.

Q. A mixture of camphor and common salt can be separated by ________.

1. distillation
2. crystallisation
3. sublimation
4. sedimentation

Q. Name the technique to separate camphor from salt.

1. Sublimation
2. Distillation
3. Separation
4. Chromatography

Q. Identify the phenomenon due to which the size of solid balls of naphthalene or camphor get reduced after few weeks.

1. Evaporation
2. Sedimentation
3. Sublimation
4. Condensation

Q.

Why do naphthalene balls disappear with time without leaving any solid behind?

1. Due to freezing

2. Due to boiling

3. Due to melting

4. Due to sublimation

Q. Identify the phenomenon due to which the size of naphthalene balls get reduced after few weeks.

1. Condensation
2. Crystallisation
3. Sublimation
4. Evaporation

Q. The process in which a solid object converts directly to its vapour state without passing through the liquid state is called ___________.

1. sedimentation
2. sublimation
3. winnowing
4. sieving

Q. How to separate salt from iodine.

Q.

12. A mixture of chalk powder and ammonium chloride can be separated by

1. distillation

2. evaporation

3. filtration

4. sublimation

Q. On heating iodine crystals, they ___________ .

1. melt
2. sublimate
3. evaporate
4. boil

Q.

Naphthalene balls get smaller in size when kept exposed to air for a few days. This happens because of sublimation.

1. True

2. False

Q.

Iodine is a toxic and greenish-yellow gas.

1. True
2. False

Q. Which amongst the following method is most suitable to separate a mixture of common salt and ammonium chloride?

1. Filtration
2. Sublimation
3. Sedimentation
4. Sieving

Q.

Which of the following techniques is used to separate components of immiscible liquids.

1. Evaporation

2. Fractional distillation

3. Sublimation

4. Filtration

Q.

What is a homogeneous mixture? Give two examples.

Q.

What are the different methods involved in separating solid-solid mixtures?

Q.

Which separation technique will you apply for the separation of the following?

Camphor from the mixture of camphor and sodium chloride

Q.

A mixture of ammonium chloride and salt is separated by the process of ______________. The volatile component in this case is ______________.

1. sublimation, salt

2. centrifugation, ammonium chloride

3. sublimation, ammonium chloride

4. centrifugation, salt

Q.

The process by which a solid directly converts into its vapour state is called ___ .

1. Sublimation

2. Condensation

3. Evaporation

4. Ebullition

Q.

Give reasons for the following.

Mixture of ammonium chloride and sodium chloride can be separated by sublimation.

Q. A mixture contains camphor and common salt. Camphor is known to go to the gas phase upon slight heating. So which process can be used to separate common salt from camphor?

1. Sublimation
2. Condensation
3. Freezing
4. Melting