A container has a volume of 6 L and holds 1 mol of gas. If the container is expanded such that its new volume is 9 L, how many moles of gas must be injected into the container to maintain a constant temperature and pressure?

Nov 13, 2017

This is based on the Gas Law PV=nRT

Explanation:

P = pressure, V = volume, n = #moles of gas, R = universal gas constant 8.31 J/mol, T = temp

So, ${P}_{1} \cdot 6 = 1 \cdot 8.31 \cdot {T}_{1}$
${P}_{1} / {T}_{1} = \frac{8.31}{6} = 1.385$

Then, when the volume is expanded, 'n' will increase to keep P and T equal:

${P}_{1} \cdot 9 = n \cdot 8.31 \cdot {T}_{1}$
The ratio ${P}_{1} / {T}_{1}$will remain constant at 1.385, so $9 \cdot 1.385 = n$