Question

At a pressure of 100 psia and 400 deg F, the specific volume of steam is 4.934 cu. ft/lb, and the specific enthalpy is 1227.5 BTU/lb. Find the internal energy at the given state, BTU/lb. attach solution.

Answer 1

$h=u+pv$

$u=h-pv=1227.5-100*4.934=1227.5 \frac{BTU}{lb}-493.4\frac{psia\cdot ft^3}{lb}=$

$=1227.5\frac{BTU}{lb}-91.3\frac{BTU}{lb}=1136.2\frac{BTU}{lb}$ .