Week 3 Install Mod Weekly Exam

The refrigerant in a mechanical compression refrigeration system absorbs and releases heat by:

• Changing its temperature.

• Changing its physical state.

• Converting energy to mass.

• Changing its molecular composition.

A general definition of refrigerant is:

• A fluid that is naturally cold.

• The fluid used in a refrigeration system for transferring heat.

• A fluid that can turn heat into mass.

• A hydrocarbon-based chemical with noble elements replacing some of the hydrogen atoms.

Refrigerants absorb heat:

• By evaporating from a liquid to a vapor.

• By condensing from a vapor to a liquid.

• By rearranging their molecular structure to form a new compound.

• By converting heat energy into additional refrigerant molecules.

Refrigerants release heat:

•  By rearranging their molecular structure to form a new compound.

• By converting refrigerant molecules into heat energy.

• By evaporating from a liquid to a vapor.

• By condensing from a vapor to a liquid.

The pressure of a saturated refrigerant can accurately be predicted:

• Only if the amount of refrigerant in the system is known.

• By multiplying the ratio of liquid to vapor times the refrigerant's base saturation temperature.

• By multiplying the refrigerant's molecular weight times the average molecular kinetic speed.

• By comparing its temperature to the corresponding pressure on a pressure-temperature chart.

The major concern with ammonia refrigerant is:

• It is poisonous and flammable.

• It is much more expensive than halogenated refrigerants.

• Its normal operating pressures are extremely high.

• It can only be used with copper, brass, and aluminum.

The chemical family that is the basic building block for most modern refrigerants is:

• Freons.

• Purons.

• Alcohols.

• Hydrocarbons.

The chemical in CFCs that contributes to ozone depletion is:

• Fluorine.

• Carbon.

• Hydrogen.

• Chlorine.

The temperature difference between the bubble point and the dew point of a zeotropic refrigerant is called:

• Superheat.

• Subcooling.

• Saturation.

• Glide.

Ozone is an oxygen molecule formed with:

• Three oxygen atoms instead of the normal two.

• Two oxygen atoms instead of the normal three.

• Chlorine to produce a new compound.

• Freon to produce a new compound.