DC -- latent heat

How is energy used when causing a solid to change into a liquid?

• heat must be applied to increase the temperature.

• pressure must be applied to reduce the volume.

• chemical reactions must occur to change the structure.

• bonds between molecules must be broken to allow them to move freely

There is no ------------ until a phase change is complete.

• polarization

• molecular movement

• temperature change

• specific heat capacity

During which phase change is energy released?

• freezing (liquid to solid)

• melting (solid to liquid)

• boiling (liquid to gas)

• sublimation (solid to gas)

The energy involved in a phase change depends on what 2 factors?

• the temperature and pressure of the environment

• the number and strength of bonds

• the outward pressure of the liquid phase

• the amount of heat and light present

In these 2 equations, what does L_f and L_v represent?

• the length of each sample

• the length of time required for phase change

• latent heat constants

Why is the energy of a phase change called latent?

• energy enters or leaves a system without causing a temperature change

• energy enters or leaves a system without altering the molecular structure

• phase changes cannot be measured experimentally

• the molecular energy causes cohesive forces

According to the graph, about how much energy is absorbed to change water to steam?

• ~550 cal/g

• ~750 cal/g

• ~200 cal/g

At which point(s) in the graph is latent heat entering the system?

• E, C, and A

• D and B

• C only

• E only

Energy is ________ when water condenses.

• absorbed

• released

Sublimation requires _______.

• energy input

• energy output