A container of oxygen has a volume of 30.0 mL and a pressure of 72.5 psi. If the pressure of the oxygen gas is reduced to 28 psi and the temperature is kept constant, what is the new volume of the oxygen gas?

THE NEW VOLUME OF THE OXYGEN GAS AT 28 PSI FROM 72.5 PSI IS 0.078 L.

Explanation:

Initial volume of the oxygen in the container = 30.0 mL = 30 / 000 L = 0.03 L

Initial pressure of the oxygen = 72.5 psi =  1 psi = 6890 pascal

Final pressure = 28 psi

Final volume = unknown

First convert the mL to L and since both pressures are in similar unit that is psi; there is no need converting them to pascal or other standard unit of pressure. They cancel each other out.

This question follows Boyle's equation of gas laws and mathematically it is written as:

P1 V1 = P2 V2

Re-arranging by making P2 the subject of the formula, we have:

V2 = P1 V1 / P2

V2 = 72,5 * 0.03 / 28

V2 = 2.175 /28

V2 = 0.0776 L

The new volume of the oxygen gas at a change in pressure from 72.5 psi to 28 psi is 0.078 L.

c) should be the answer.