# The volume of 4.0 cubic meters of gas is kept under constant pressure. Its temperature is increased from a minus 73 degrees Celsius to 127 degrees Celsius. What is the new volume of the gas?

We follow Charles' law: for a given quantity of gas, at CONSTANT pressure, $V$ $\propto$ $T$. $T$ is specified to be absolute temperature.
Since $V$ $\propto$ $T$, $V$ $=$ $k T$. Alternatively, (if we solve for $k$),
$k = {V}_{1} / {T}_{1} = {V}_{2} / {T}_{2}$.
So, ${V}_{2} = \frac{{V}_{1} \times {T}_{2}}{T} _ 1$ $=$ $\frac{4.0 \cdot {m}^{3} \times 400 \cdot \cancel{K}}{200 \cdot \cancel{K}}$ $=$ ??*m^3.