Question

1. Consider two perfect gases at low pressure, A and B. A and B have different chemical identities, but the number of moles of the two gases is the same. Would a plot of the V/T isobar be different for the two gases? If so, explain how the plots would differ. If not, explain why

2. Calculate the molar volume of a perfect gas at STP and SATP

Answer 1

1) The plot, V vs T at constant pressure, for two equi molar gases is not same. Because the density of the two different gases is not same. By inceasing the rempartaure the volume of the gas increases, leading to decrease in its density. Therefore the graph between V and T at constant temperature for two different gases is not same.

2) STP stands for standard temperature and pressure, i.e. T = 273.15 K or 0 ^oC, P = 1 atm

the perfect or ideal molar gas equation is PV = RT, R is a gas constant having a value 0.0821 lit. atm. K^-1. mol^-1

molar volume (V) = RT/P = (0.0821*273.15)/1 = 22.42 lit.

SATP stands for standard ambient temperature and pressure, i.e. T = 298.15 K or 25 ^oC, P = 1 atm

molar volume (V) = RT/P = (0.0821*298.15)/1 = 22.478 lit.