Evaporation

Q. Question 3
Why does our palm feel cold when we put some acetone or petrol or perfume on it?

Q. of an egg is NOT a chemical change.

1. Boiling
2. Eating
3. Breaking

Q. Amongst W, X, Y, and Z, which water molecule would evaporate quickly and turn to water vapour?

1. W
2. Y
3. X
4. Z

Q. How will you obtain common salt from sea water?

1. Filtration
2. Evaporation
3. Sedimentation
4. Handpicking

Q.

How will you classify the reaction of the formation of water from hydrogen and oxygen gases?

Q. Chemical changes result in the formation of new substances.

1. True
2. False

Q.

During evaporation, temperature of the water does not remain constant.

1. True

2. False

Q. Water in a clay pot will be cooler because of continuous ___ of water through the pores.

1. Evaporation
2. Convection
3. Condensation
4. None of these

Q. Why does evaporating sweat cools human body?

1. Condensation
2. Evaporate cooling
3. Melting
4. Evaporate heating

Q. Drying of wet clothes on a sunny day takes place due to the phenomenon of ______.

1. condensation
2. evaporation
3. sublimation
4. deposition

Q.

To get her house whitewashed, an officer bought 10 kg of quicklime from the market and dissolved it in 30 litres of water.
She noticed that the solution warmed up even when it was not being heated.
What is the corresponding product formed and the type of reaction involved?

Q.

The process of evaporation of water from the aerial parts of plants especially in leaves is called as __.

Q.

Explain the principle of evaporation process.

Q.

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

Sodium chloride from its solution in water.

Q.

Give one property in which a solution of sugar in water resembles a mixture of sugar and sand.

Q. Pure salts can be extracted from its solution using the method called .

1. crystallisation
2. filtration
3. vapourisation

Q.

The effective collision of molecules increases because of the increase in their

1. Mechanical energy

2. Potential energy

3. Kinetic energy

4. Chemical energy

Q.

Which of the following is a chemical change?

1. Cooking of vegetables
2. Cutting of fruits
3. Boiling of water
4. Melting of solids

Q. Geetika poured 20 g of salt into 200 mL of water in a beaker. She stirred the water to dissolve the salt completely. Then she heated the solution until it reduced to half.

1. 40 g
2. 0 g
3. 10 g
4. 20 g

Q. Dyes from ink can also be separated through :

1. evaporation
2. distillation
3. filtration
4. centrifugation

Q.

A body at $110°C$ is dropped into water at $100°C$. What happens to the quantity of water in the container?

1. remains the same

2. increases

3. decreases

4. the body converts to the liquid state

Q.

Give any two examples for which evaporation is used.

Q. Pure salts can be extracted from its solution using the method called .

1. filtration
2. vapourisation
3. crystallisation

Q.

Which type of mixture is separated by evaporation?

Q. Pure salts can be extracted from its solution using the method called .

1. vapourisation
2. crystallisation
3. filtration