Question

A closed system executes a series of processes for which two of the three quantities W, Q and ΔU are given for each process. Find the value of the unknown quantity in each case.

a) W = + 10 Hp , Q = + 500 KJ/min, ΔU = ?

b) W = 65 KJ, Q =?, ΔU= -25 KJ

c) W = ?, Q = + 25KJ, ΔU = 0 

Answer 1

a)- $Q = w + \Delta U$

$8333.33 = 7460 + \Delta U$

$\Delta U = 873.33 W$

b)- $Q = w + \Delta U$

$Q = 65-25$

= 40 KJ

c)- $Q = w + \Delta U$

$25 = W +0$

$W = 25$