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?

1 Answer

The initial volume of the gas was 0.255 dm³.

Explanation:

This is an example of Charles' Law.

V1T1=V2T2

V1 = ?; T1 = (50. + 273.15) K = 323 K

V2 = 212 cm³; T2 = (-5.0 + 273.15) K = 268.2 K

V1=V2×T1T2 = 212 cm³ ×323K268.2K = 255 cm³

V1 = 255 cm³ × (1dm10cm)3 = 0.255 dm³

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.