Question
(a) Explain
(i) how gas molecules exert a force on a solid surface,
(ii) the increase in pressure of a gas when its volume is decreased at constant temperature.
(b) A cylinder of volume \(5.0 × 10^3 cm^3\) contains air at a pressure of \(8.0 × 10^5\) Pa.
A leak develops so that air gradually escapes from the cylinder until the air in the cylinder is at atmospheric pressure. The pressure of the atmosphere is \(1.0 × 10^5\) Pa.
Calculate the volume of the escaped air, now at atmospheric pressure. Assume that the temperature stays constant.
volume = ……………………… \(cm^3\)
Answer/Explanation
Answer:
(a) (i) (Force exerted when) molecules hit wall / surface / solid (and rebound) Allow (force) due to momentum change in collision
(ii) Molecules/atoms/particles collide with / push against walls more (often)
(so) bigger force / push
NOT collide faster
(b) \(P_1 V_1=P_2 V_2\) OR PV = constant
\(8.0 \times 10^5 \times 5000=1 \times 10^5 \times V_2\)
\(V_2=40000 cm^3\)
Volume escaped =40000-5000=35000 \(cm^3\)