# An ideal gas in a sealed container has an initial volume of 2.70 L. At constant pressure, it is cooled to 19° C where its final volume is 1.75 L. What was the initial temperature?

This question is ill-proposed, but Charles' Law applies, ${V}_{1} / {T}_{1} = {V}_{2} / {T}_{2}$, temperatures are absolute values.
${T}_{1}$ $=$ ${V}_{1} / {V}_{2} \times {T}_{2}$ $=$ $\frac{2.70 \cdot L}{1.75 \cdot L} \times 292 \cdot K$ $=$ ??K