Chemistry - Ideal Gas Question with Solution | TestHub
An ideal gas, Xn, is taken in a container connected to frictionless, massless piston. The pressure of gas is constant (always equal to the atmospheric pressure). The expected graph for the variation of volume of gas with the change in temperature was to be like fig. I, but the actual graph is like fig II. The deviation was attributed to dissociation of gas as: Xn(g) → n X(g). If the yield of this reaction is only 60%, the value of n is
Answer:
Solution:
At constant pressure V ∝ (total moles) x T, so the slope dV/dt is proportional to the number of moles of gas particles.
Expected slope (no dissociation): (50.2 - 49.9)/20 = 0.015 l/°C... using the marked points: (50.2 - 49.9)/(20) = 0.3/20.
Actual slope: (49.1 - 47.9)/20 = 1.2/20.
Ratio of slopes = 1.2/0.3 = 4 = moles after dissociation / moles before = 1 + alpha(n - 1), with alpha = 0.60.
1 + 0.6(n - 1) = 4 ⇒ n - 1 = 5 ⇒ n = 6.
