Thermodynamics! help before my final!?

Question

1.The inside wall temperature of a furnace wall 1.5 ft thick is 1900 deg F, and the average thermal conductivity is 0.61 Btu/h-ft -deg F. The heat transfer coefficient on the outside is about 7 Btu/h ft^2- deg R, while the outside air is at 70 deg F. Determine the heat loss rate through 1 ft^2 of the furnace wall.

2.A wet refrigerant vapor comprises 75% saturated liquid and 25% saturated vapor by mass. The specific volume for the saturated liquid is 0.851 L/kg, and that for the saturated vapor is 19.7 L/kg. Determine the density of the wet vapor (n kg/L)

the answer was .18 kg/L

Thanks for the help!

Answer 1

Well for the second one I would imagine that it is like this...

(0.75)(.851 L/kg) + (0.25)(19.7 L/kg) = 5.563 L/kg ==> 0.180 kg/L