Condensation and Evaporation

Question 1

What in condensation?

Answer 1

When gases turn to liquids.

Question 2

What happens when a gas cools?

Answer 2

The particles in the gas slow down and lose kinetic energy.

Question 3

What forces in the gas pull the particles close together?

Answer 3

The attractive forces.

Question 4

What must happen for condensation to occur?

Answer 4

If the temperature gets cold enough.

The gas particles get close enough together.

Question 5

What does water vapour do in the air?

Answer 5

It condenses when it comes in contact with cold surfaces.

Question 6

What is the steam you see rising from a boiling kettle?

Answer 6

Invisible water vapour condensing for form tiny water droplets as it spreads into cooler air.

Question 7

What is evaporation?

Answer 7

When liquid turns to gas.

Th particles escape from the liquid.

Question 8

The particles can evaporate from a liquid at what temperatures?

Answer 8

Temperatures that are much lower than the liquid’s boiling point.

Question 9

The particles near the surface of the liquid do what?

Answer 9

Escape and become gas particles.

Question 10

What must the particles in the liquid be doing to escape?

Answer 10

Travel in the right direction.

Travel fast enough to over come the attractive forces of the other particles in the liquid.

Question 11

Fastest particles =

Answer 11

Most likely to escape the liquid.

Question 12

When particles leave the liquid what happens?

Answer 12

The average speed and kinetic energy of the remaining particles decrease.

Question 13

The decrease in the average particle energy means what?

Answer 13

The temperature of the remaining liquid falls.

Question 14

Give an example of evaporation.

Answer 14

When you exercise you get hot so therefore sweat.

As the water evaporates off your body it cools you down.

Question 15

Rates of condensation and evaporation can ____

Answer 15

Vary.

Question 16

The rate of evaporation will be faster if what happens.

Name 4 things?

Answer 16

Temperature is higher.
Density is lower.
Surface area is larger.
Airflow over the liquid is greater.

Question 17

In evaporation why is it good if the temperature is higher?

Answer 17

Average particle energy will be higher.

More particles will have enough energy to escape.

Question 18

In evaporation why is it good if the density is lower?

Answer 18

Forces between the particles will be weaker.

Particles can overcome the forces and escape.

Question 19

In evaporation why is it good if the surface area is larger?

Answer 19

More particles able to flow near the surface and escape the liquid.

Question 20

In evaporation why is it good if the airflow over the liquid is greater?

Answer 20

Lower the concentration of an evaporating substance in the air its evaporating into, the higher the rate of evaporation .

Question 21

What does a greater air flow mean?

Answer 21

Air above the liquid is replaced more quickly.

As concentration in the air is lower.

Question 22

The rate of condensation will be faster when…

Name 4 things?

Answer 22

Temperature of the gas is lower.
Temperature of the surface the gas touches is lower.
Density is higher.
Airflow is less.

Question 23

In condensation why is it good if the temperature of the gas is lower?

Answer 23

Average particle energy in gas is lower.

More particles slow down to clump together and fom liquid droplets.

Question 24

In condensation why is it good if the density is higher?

Answer 24

Forces between particles will be stronger.

Few particles will have enough energy to overcome forces so will have to clump together and form a liquid.

Question 25

In condensation why is it good if the airflow is less?

Answer 25

Concentration of the substances in the air will be higher.

Rate of condensation will be greater.