Hydrogen, acting as a van der Waals gas, is at 1800kPa and 280K. 1) What is volume expansivity, ? 2) What is the isothermal compressibility, ? 3)

Hydrogen, acting as a van der Waals gas, is at 1800kPa and 280K. 1) What is volume expansivity, β? 2) What is the isothermal compressibility, α? 3) What is the difference between cp and cv? (Use the Mayer relation) 

P = RT v − b − a v 2

a = 27*R^2*Tcrit^2/(64Pcrit)

b = RTcrit/8Pcrit