Question

Two flasks of equal volume connected by a narrow tube (of negligible volume) are at ${27}^{\circ }C$ and contain 0.70 mole of $H_2$ at 0.5 atm. One of the flasks is then immersed into a hot bath, kept at ${127}^{\circ }C$, while the other remains at ${27}^{\circ }C$. Calculate the final pressure.

• A. 0.5714 atm
• B. 0.2713 atm
• C. 0.8314 atm
• D. 17.24 atm

Answer 1

The correct option is A

0.5714 atm

$PV=nRT$ $n=n_1+n_2=0.7$

$0.5(V+V)=0.7R\times 300;2V=\frac{0.7R\times 300}{0.5}$

$P_1^{\prime }=P_2^{\prime }$ $\frac{n_1^{\prime }R\times 300}{V}=\frac{n_2^{\prime }R\times 400}{V}$

$n_1^{\prime }=n_2^{\prime }\times \frac{4}{3},n_1^{\prime }+n_2^{\prime }=0.7$

$n_1^{\prime }=0.4,n_2^{\prime }=0.3$

$P_1^{\prime }=\frac{n_{1}R\times 300}{V}=\frac{0.4R\times 300}{0.7R\times 300}=\frac{4}{7}atm\approx 0.57atm$