A mass of He gas occupies a volume V at standard temperature and pressure.What volume is occupied if the mass is halved,the absolute temperature doubled,and the pressure increased by a third?
A)(3/16)V
B)(4/3)V
C)(3/4)V
D)(3/8)V
E)(1/3)V

Question

Quizplus · Accepted Answer

We can use the combined gas law to solve this problem, which states that:

(P1V1)/T1 = (P2V2)/T2

where P is pressure, V is volume, and T is temperature.

Let's label the initial conditions as 1 and the final conditions as 2:

- Mass is halved, so the number of moles is halved. Since He gas is monatomic, its mass is directly proportional to the number of moles, so the mass of He is also halved. 
- Absolute temperature is doubled, which means T2 = 2T1. 
- Pressure is increased by a third, which means P2 = (4/3)P1.

Substituting these values into the combined gas law, we get:

(P1V1)/T1 = [(4/3)P1V2]/(2T1)

Simplifying, we get:

V2 = (3/4)V1

So the final volume is 3/4 of the initial volume, which means the best choice is C.

A Mass of He Gas Occupies a Volume V at Standard