Question

Consider two 5 L chambers. In one, there are 5.00 g O₂, and in the other there are 5.00 g He. Which has the higher pressure at room temperature?
A) O₂
B) Не
C) They have equal pressures
D) Not enough info

Answer 1

Answer:

He have higher pressure at room temperature.

Explanation:

It is given that both the gases are kept in 5 L chambers.

Therefore, volume is constant.

Also, they both are at room temperature, so temperature is also constant.

Now, number of moles of $O_2$ = $\dfrac{Given\ mass}{Molecular \ mass}=\dfrac{5}{32}=0.16\ mol.$

Also, number of moles of He =$\dfrac{Given\ mass}{Molecular \ mass}=\dfrac{5}{4}=1.25\ mol.$

Now, according to GAS LAW,

$PV=nRT$  ( all terms have their usual meaning).

In this case, V, R and T are constant.

So, pressure is directly proportional to n i.e number of moles.

So, moles of He is more than moles of $O_2$.

Therefore, He have higher pressure at room temperature.

Hence , this is the required solution.