Latent Heat and Change of State in Matter

The video tutorial explains the concept of specific latent heat, which is the heat energy required to change the state of a unit mass of a substance without a change in temperature. An experiment is conducted using ice cubes and a thermometer to observe the constant temperature during the phase change from ice to water and from water to steam. The energy supplied during these changes is used to break intermolecular forces, hence the temperature remains constant. This energy is termed latent heat because it is not reflected in temperature changes.

What does the term 'latent' in latent heat refer to?

• Active

• Dormant

• Visible

• Hot

What is the specific latent heat?

• The heat required to increase the pressure of a substance

• The heat required to decrease the volume of a substance

• The heat required to change the state of a unit mass of a substance without changing its temperature

• The heat required to change the temperature of a substance

What is the initial temperature of the ice cubes in the activity?

• 100 degrees centigrade

• 50 degrees centigrade

• 0 degrees centigrade

• 10 degrees centigrade

During the melting of ice, what happens to the temperature as heat is supplied?

• It increases

• It remains constant

• It fluctuates

• It decreases

At what temperature does water start boiling in the activity?

• 100 degrees centigrade

• 50 degrees centigrade

• 0 degrees centigrade

• 150 degrees centigrade

What happens to the temperature of water as it is heated from 0 degrees centigrade?

• It decreases

• It fluctuates

• It remains constant

• It increases

What is observed when boiling water is converted to steam?

• The temperature fluctuates

• The temperature remains constant

• The temperature decreases

• The temperature increases

What is the role of energy supplied during a change of state?

• To break intermolecular forces

• To change color

• To increase temperature

• To decrease temperature

Why does the thermometer not register a rise in temperature during a change of state?

• The energy is used to break intermolecular forces

• The thermometer is broken

• The energy is lost to the surroundings

• The thermometer is not sensitive enough

Why is the heat supplied during a change of state called latent heat?

• Because it is very high

• Because it is very low

• Because it is not recorded by the thermometer

• Because it is visible