# If a sample of neon gas occupies a volume of 2.8L at 1.8 atm. what will its volume be at 1.2 atm?

Jun 14, 2014

This problem asks us to make a comparison of the pressure and volume of a gas. The ratio of pressure and volume can be determined using Boyle's Law which is defined by the inverse relationship pressure to volume in the equation ${P}_{i} {V}_{i} = {P}_{f} {V}_{f}$ when Temperature is held constant.

For this question we identify the knowns and unknowns.

${P}_{i} = 1.8 a t m$
${V}_{i} = 2.8 L$
${P}_{f} = 1.2 a t m$
V_i = ??? L

The equation ${P}_{i} {V}_{i} = {P}_{f} {V}_{f}$ can be rearranged algebraically to $\frac{{P}_{i} {V}_{i}}{{P}_{f}} = {V}_{f}$.

$\frac{\left(1.8 a t m\right) \left(2.8 L\right)}{1.2 L} = {V}_{f}$

${V}_{f} = 4.2 L$

Notice that in Boyle's law as the pressure decreases the volume will increase as this is an inverse relationship between pressure and volume.