Thermodynamics

Question-1 True or false?

(a) On the Celsius scale, the boiling point of water at standard pressure is 100.00°C.

(b) Doubling the absolute temperature of an ideal gas at fixed volume and amount of gas will double the pressure.

(c) The ratio PV/mT is the same for all gases in the limit of zero pressure.

(d) The ratio PV/nT is the same for all gases in the limit of zero pressure.

(e) All ideal gases have the same density at 25°C and 1 bar.

(f) All ideal gases have the same number of molecules per unit volume at 25°C and 10 bar.

1. Solutions

(a) True: at standard pressure, the Celsius scale uses 100°C as a reference point.

(b) True: the pressure of an ideal gas is directly proportional to its temperature.

(c) False: Avogadro's hypothesis refers to the number of molecules or atoms of a given

volume. Two equal volumes under the same conditions need not have the same mass (m)

even though they have the same number of molecules.

(d) True: see (c) (e) False: see (c) (f) True: see (c)