Chemistry - Thermochemistry Question with Solution | TestHub
An intimate mixture of carbon monoxide gas and the theoretical amount of air at 27°C and a total pressure of 1 atm, is exposed in a closed rigid vessel. If the process occurs under adiabatic condition, then using the following data, answer the following questions. Take R = 2 cal/K-mol and 27°C = 300 K.
Given: (i) CP,m(N2) = 7.0 cal/K-mol (ii) CP,m(CO2) = 9.5 cal/K-mol (iii) CO(g) + 1/2O2(g) → CO2(g), ΔH = -34.0 kcal, independent of temperature (iv) Air contains 20% O2 and 80% N2 by volume
What will be the maximum temperature (approximately) attained if the process occurs in adiabatic container?
Options:
Answer:
Solution:
Take CO + 1/2O2 + 2N2 → CO2 + 2N2 (0.5 mol O2 comes with 2 mol N2). Gas moles 3.5 → 3, so Δn = -0.5. ΔU = ΔH - Δn RT = -34.0 + 0.5×2×300/1000 = -33.7 kcal. Products absorb this at constant volume: CV = 7.5 + 2(5.0) = 17.5 cal/K. ΔT = 33700/17.5 = 1926 K, so T = 300 + 1926 ≈ 2225 K. This is option (c).
