A level physics

Jasmine ngjiamin SG

A sealed 75 m3 tank is filled with 9000 moles of an ideal gas at an initial temperature of 250 0C. The gas is heated to a final temperature of 320 0C. The final pressure of the gas, in MPa, is closest to:

Jasmine ngjiamin SG

This is part two of the question :)

Calculate the heat transferred to the gas in the 75 m3 tank during the above heating process, given that the tank remain intact and none of the gas escaped. Give your answer in MJ.

eagle SG

Remember to work temperature in Kelvins only since that's the SI units

P1 = nRT1 / V = 9000 * 8.31 * (250 + 273) / 75 = 521535 Pa = 0.5215 MPa

Since volume is constant,

P1/T1 = P2/T2
0.5215 / (250+273) = P2 / (320+273)
P2 = 0.59 MPa

Since volume is a constant, therefore, work done on/by gas = 0
From first law of thermodynamics,
change in internal energy = heat supplied to gas + work done on gas

Heat supplied
= change in internal energy
= (3/2) (9000)(8.31)(320+273) - (3/2) (9000)(8.31)(250+273)
= 7852950 J
= 7.85 MJ

Good luck for your mid years :)