Week 2 lecture 2

Question 1

substance composed of a single chemical species, which may exist in more than one phase

Answer 1

pure substance

Question 2

molecules are arranged in a 3d pattern (lattice) that is repeated throughout

Answer 2

solid

Question 3

molecules are no longer at fixed positions relative to each other and they can rotate and translate fully

Answer 3

liquid

Question 4

the molecules are far apart from each other, and a molecular order is non-existent

Answer 4

gas

Question 5

a liquid which is not about to vapourise

Answer 5

compressed liquid

Question 6

liquid that is about to vapourise

Answer 6

saturated liquid

Question 7

vapour that is not about to condense

Answer 7

superheated vapour

Question 8

at a given pressure, the temperature at which which a pure substance changes phase

Answer 8

saturation temperature (T sat)

Question 9

at a given temperature, the pressure at which a pure substance changes phase

Answer 9

saturation pressure (P sat)

Question 10

Ideal gas equation

Answer 10

PV = nRT

Question 11

Gibbs Phase Rule equation

Answer 11

number of degrees of freedom = number of chemical species - number of phases + 2

Question 12

temperature and pressure at which the three phases (gas, liquid and solid) of that substance coexist in thermodynamic equilibrium

Answer 12

triple point

Question 13

end point of phase equilibrium

Answer 13

critical point

Question 14

for a single molecular species system as the highest temperature and pressure (Tc, Pc) at which liquid and vapour phases can exist in equilibrium

Answer 14

critical point

Question 15

condition at which the properties of the gas phase (vapour phase) and liquid phase in equilibrium become identical

Answer 15

critical point

Question 16

deviation of a real gas from ideal gas behaviour

Answer 16

compressibility factor (Z)

Question 17

the ____ the deviation from the ideal gas law, the closer to Z is to 1

Answer 17

lower

Question 18

the lower the deviation from the ideal gas law, the ______to Z is to 1

Answer 18

closer

Question 19

equation for reduced temperature

Answer 19

reduced temperature = temperature/critical temperature

Question 20

equation for reduced pressure

Answer 20

reduced pressure = pressure/critical pressure

Question 21

reduced properties are _______

Answer 21

dimensionless

Question 22

generalised gas equation with compressibility factor

Answer 22

PV = ZnRT

Question 23

critical compressibility factor equation

Answer 23

Zc = reduced pressure*reduced volume / R * reduced temperature