Phase Change Graphs Practice- Friday 2/28

What is the latent heat of fusion?

• The energy required to change a substance from liquid to gas at its boiling point.

• The amount of energy required to change a substance from solid to liquid at its melting point without changing its temperature.

• The heat energy released when a substance freezes.

• The energy needed to raise the temperature of a substance by one degree Celsius.

What occurs between points B and C on a phase change graph?

• The substance is losing energy and changing from a liquid to a solid (freezing).

• The substance is gaining energy and changing from a solid to a liquid (melting).

• The substance is gaining energy and changing from a liquid to a gas (evaporation).

• The substance is losing energy and changing from a gas to a liquid (condensation).

What is melting point?

• The temperature at which a solid becomes a liquid.

• The temperature at which a liquid becomes a gas.

• The temperature at which a gas condenses into a liquid.

• The temperature at which a solid sublimates directly into a gas.

What happens to the energy of a substance during a phase change?

• The energy remains constant throughout the phase change.

• The energy of a substance always increases during a phase change.

• The energy of a substance either increases or decreases, depending on whether it is melting, boiling, freezing, or condensing.

• The energy of a substance is only affected during melting and boiling.

How does pressure affect phase changes?

• Increasing pressure raises the boiling point and can lower the melting point.

• Pressure has no effect on phase changes.

• Increasing pressure lowers the boiling point and raises the melting point.

• Pressure only affects the solid phase of substances.

Why is understanding phase change graphs important?

• It helps in predicting how substances behave under different temperature and pressure conditions, which is essential in various scientific and industrial applications.

• It allows scientists to create new elements and compounds.

• It is only relevant for studying gases and liquids, not solids.

• It simplifies the process of measuring temperature and pressure in experiments.

What does it mean when a substance is gaining energy?

• It is absorbing heat, which can lead to a phase change from solid to liquid (melting) or liquid to gas (boiling).

• It is losing heat, which causes it to solidify.

• It is undergoing a chemical reaction that releases energy.

• It is maintaining a constant temperature without any phase change.

What is boiling point?

• The temperature at which a liquid becomes a gas.

• The temperature at which a solid melts into a liquid.

• The temperature at which a gas condenses into a liquid.

• The temperature at which a liquid freezes into a solid.

What is the latent heat of vaporization?

• The energy required to change a substance from solid to liquid.

• The amount of energy required to change a substance from liquid to gas at its boiling point without changing its temperature.

• The heat energy released when a gas condenses into a liquid.

• The energy needed to raise the temperature of a substance by one degree Celsius.

At what temperature does water boil?

• 90°C

• 100°C

• 110°C

• 95°C