# Thermodynamics

posted by
**Janus**
.

What is the specific volume of a gas at 180psia & 90°F when its density is 0.0892 lb/cu ft at 14.7psia & 32°F. Calculate its gas constant & the appropriate molecular weight.

Checking:

@ 14.7psia & 32°F

where;

v= 1/0.0892lb/cu.ft = 11.2108cu.ft/lb

v= 19372.2624 cu.in/lb

R=Gas Constant

R=Pv/T

R=(14.7lb/sq.in)x(19372.2624 cu.in/lb)x(1ft/12in))/(492°R)

R= 48.2338 (ft lb(force)/lb(mass) °R)

Solving Specific Volume @ 180psia & 90°F

v=RT/P

v= 48.2338 (ft lb(force)/lb(mass) °R)x(550°R) / (25920lb/sq.ft)

v= 1.0235lb/cu.ft

Unsure about Molecular Weight

p= 1/1.0235lb/cu.ft =0.977cu.ft/lb

MW=p(RT/P)

MW= 0.977cu.ft/lb (48.2338 (ft lb(force)/lb(mass) °R) x 550°R / (25920lb/sq.ft))

MW= 0.9999