Chemistry - Thermodynamics - I Question with Solution | TestHub
Two rigid adiabatic vessels A (volume = 4 L) and B (volume = 6 L), which initially contains two gases at different temperatures, are connected by a pipe of negligible volume. The vessel A contains 2 moles of Ne gas (CP,m = 5 cal/K-mol) at 300 K and vessel B contains 3 moles of SO2 gas (CP,m = 8 cal/K-mol) at 400 K. What is the final pressure (in atm) when the valve is opened and 12 kcal heat is supplied through it to the vessels?
Options:
Answer:
Solution:
Rigid vessels, so W = 0 and Q = Δ U for the whole system. CV,m(Ne) = 5 - 2 = 3 cal/K-mol, CV,m(SO2) = 8 - 2 = 6 cal/K-mol (R = 2 cal/K-mol). 12000 = (2 × 3 + 3 × 6)Tf - (2 × 3 × 300 + 3 × 6 × 400) = 24Tf - 9000, so Tf = 21000/24 = 875 K. Total n = 5 mol, V = 10 L, P = nRT/V = 5 × 0.08 × 875/10 = 35 atm. Matches (c).
