Question

A sample of gas has an initial volume of 33.8 L at a pressure of 1.5 atm .

If the sample is compressed to a volume of 14.5 L , what is its pressure?
Express the pressure in atmospheres to three significant figures.

Answer 1

Solution:
As there are no any special notes than we assume that process occurs at the constant temperature. Than we use the Boyle’s law:

PV=k, where

P - is the pressure of the gas;
V - is the volume of the gas,;
k - is a constant;

If system changes it’s state from state 1 to state 2, than
P1V1= P2V2 (=k);
and the new pressure is:
P2 = P1V1 / V2.

Do the calculation:
P2 = 33.8 L * 1.5 atm / 14.5 L = 3.50 atm.

(Important to write zero in the end as it is significant figure)

Answer:
The new pressure is 3.50 atm.