STG330 Topic 2

If its pressure is greater than the saturation pressure at a given temperature, the substance is

• a compressed liquid

• A superheated vapor

• A subcooled vapor

• a saturated mixture

• Not enough information

Comparing superheated vapors to saturated vapors, what is NOT true?

• The enthalpy of the superheated vapor is higher

• The internal energy of the superheated vapor is higher

• The pressure of the superheated vapor is higher

• The specific volume of the superheated vapor is higher

A rigid tank holds 8 kg of water, 2 kg of which are liquid. What is the quality?

• 0.75

• 0.2

• 0.25

• 0.8

Water always boils at 100C.

• True

• False

Answer explanation

The boiling-point temperature depends on the pressure! Water only boils at 100 C for 1 atm (about 100 kPa) of pressure.

Subcooled liquid properties depend more strongly on...

• Temperature

• Pressure

• They depend on both temperature and pressure equally

The Unit-corn would like to remind you that all properties pulled from the tables are per unit mass!

• Got it, Unit-corn! I'll adjust the problem for my own mass.

• Thanks, Unit-corn! I won't forget to multiply by mass.

• You got it, Unit-corn! I'll check my units and get rid of the 'per mass' part.

• No problem, Unit-corn! I always make sure I'm answering the question completely.

The vaporization point is the same as the ________ point.

Any other comments or concerns for Topic 2 material?