One-half kmol of carbon monoxide (co) in a piston- cylinder assembly undergoes a process from p1 = 150 kpa, t1 = 300 k to p2 = 500 kpa, t2 = 420 k. for the process, w = -300 kj. employing the ideal gas model, determine: (a) the heat transfer, in kl. (b) the change in entropy, in kj/k.

Ahe-xe mixture containing a 0.75 mole fraction of helium is used for cooling electronics in an avionics application. at a temperature of 300 k and atmospheric pressure, calculate the mass fraction of helium and the mass density, molar concentration and molecular weight of the mixture. if the cooling capacity is 10 l, what is the mass of the coolant?