A sample of hydrogen has an initial temperature of 50.° C. When the temperature is lowered to -5.0° C, the volume of hydrogen becomes 212 cm3. What was the initial volume of the hydrogen in dm3?
The initial volume of the gas was 0.255 dm³.
This is an example of Charles' Law.
This makes sense. The initial Kelvin temperature was about 20 % higher than the final temperature. The original volume must also have been about 20 % (40 cm³) larger than the final volume.