Question

You compress 0.5 moles of a gas at constant pressure from 4 liters to 1 liter while 2625 J of heat is removed, the temperature drops by 180.4 K, and Eth drops by 1875 J. How much work energy is added to the gas?

Answer 1

The work energy added to the gas is

W = -72.48472 kJ

Step-by-step explanation:

For constant pressure process

Work is given W = p×
`(V_(f) - V_i)`

However dH = m×
`c_(p) (T_2-T_1)` = 1875 J

For mass m, dQ = 2625 J

That is m×1875 = 2625 or m = 2625/1875 = 1.4 kg

Therefore work doneper unit mass of gas is -W = p×(v₂ - v₁)

but pv = RT therefore work done per unit mass = -R×(T₂ - T₁) = -R×ΔT and

ΔT = 180.4K

Work done = -1.4×0.287×180.4 = -72.48472 kJ