The Properties Of Vapours

Question 1

What is a gas

Answer 1

Substance that has a single defined thermodynamic state at room temp

Question 2

What is a vapour

Answer 2

Substance that is a mixture of two phases- gas and liquid. Has experienced some sort of phase change.

Question 3

Sensible heat

Answer 3

Energy transferred to or from a substance that results in a temperature change without a phase change.

Question 4

Latent heat

Answer 4

Energy absorbed or released by a substance during a phase change (melting, boiling, condensation) without a change in temperature.

Question 5

Dryness fraction x

Answer 5

How much of our vapour mixture is liquid and how much is gas, how far along the boiling line we are. A
1kg of steam vapour that has boiled to 100% gas phase has a dryness fraction of 0. For 100% liquid, x would be 0.

Question 6

Superheating

Answer 6

Superheating is a term given to adding heat to a dry gas. In the case of steam, it mean heating the water gas above the dry saturation point (boiling point), without allowing it to return to liquid phase.
Further heating of saturated vapour increases its temperature while keeping into the vapour phase. At the current pressure, thus raises the temperature of the Vapor above its saturation temp. It does not contain any liquid droplets