# A 5.00 liter balloon of gas at 25 C is cooled to 0 C. What is the new volume (liters) of the balloon?

We use $\text{Charles' Law}$, ${V}_{1} / {T}_{1} = {V}_{2} / {T}_{2}$
$T$ is specified to be $\text{Absolute Temperature}$:
${V}_{2} = {V}_{1} / {T}_{1} \times {T}_{2}$
$= \frac{5.00 \cdot L}{298 \cdot K} \times 273 \cdot K \cong 4.5 \cdot L$