States of Matter - Result Question 11
####11. If $500 mL$ of gas $A$ at 400 torr and $666.6 mL$ of $B$ at 600 torr are placed in a 3 litre flask, the pressure of the system will be
(a) 200 torr
(b) 100 torr
(c) 550 torr
(d) 366 torr
[1999]
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Solution:
- (a) Applying Boyle’s law $P_1 V_1=P_2 V_2$ for both gases
$\frac{500}{1000} \times 400=P \times 3 \Rightarrow P=\frac{200}{3}$
$600 \times \frac{666.6}{1000}=P^{\prime} \times 3 \Rightarrow P^{\prime}=\frac{400}{3}$
$\Rightarrow P_T=P+P^{\prime}=\frac{200}{3}+\frac{400}{3}=\frac{600}{3}=200$ torr
Real life application of Boyle’s law: when we fill bike tier with air with pump, the gas molecules inside the tire get compressed and packed closer together. This increase the pressure of the gas and it starts to push against the wall of the tire and the tires becomes tighter.
