Question

Consider two cylinders of gas identical in all respects except that one contains O₂ and the other He. Both hold the same volume of gas at STP and are closed by a movable piston at one end. Both gases are now compressed adiabatically to one-third their original volume. Which gas will show the greater pressure increase?
A)It's impossible to tell from the information given.
B)the oxygen (O₂)
C)Neither; both will show the same increase.
D)the He

Answer 1

Answer:

D) He

Explanation:

For adiabatic change

$PV^\gamma = constant$

\frac{P_2}{P_1} =(\frac{V_1}{V_2} )^\gamma

$\frac{P_2}{P_1} =(\frac{3}{1} )^\gamma$

$P_2 = P_1 3^\gamma$

As the value of  \gamma increases, P_2 increases.

\gamma for He is 1.67 and \gamma for O₂ IS 1.4

Naturally The value  of P_2 is greater  for He. Increase in pressure for He is greater.