Heat and Thermodynamics

Problems

1. Calculate the temperature of inversion for hydrogen (H₂) if the critical temperature is 22 K.

    

   Ans. 148.5 K

2. Calculate the temperature of inversion of oxygen (O₂) when

   a = 1.32 litre² × atmosphere per mole² and

   b = 3.12 3 10⁻² litres per mole.

    

   Ans. 1048 K

3. Calculate the drop in temperature produced by the adiabatic throttling expansion of air from 215 atmospheres to 1.2 atmospheres, the air being initially at 0°C. What would be the cooling if the expansion were reversible doing external work? Assume that air obeys Van der Waals’ equation with

   a = 13.4 × 10⁵ atmospheres × cm⁶ per gm mole and

   b = 36.5 cc/gm. mole and

   C_p = 6.95 cal per gm. mole

   γ = 1.4

    

   Ans. 61.8°C, 211°C

4. Given the values of Van der Waals’ constants a and b for argon ...