Question

An ideal gas in a sealed container has an initial volume of 2.35 L. At constant pressure, it is cooled to to 18°C where its final volume is 1.75 L. What was the initial temperature?

Answer 1

391 K or 118 degrees Celsius

Explanation:

We use Charles' Law:
`V_1/T_1=V_2/T_2`

Plug in the values:
`(2.35L)/T_1=(1.75L)/(291K)`

And don't forget to convert degrees Celsius to Kelvin! Just add 273.

Solve the algebra:
`2.35L` x `291K` = `683.85 L*K`

`683.85 L*K` x `1/(1.75L)` = `391K`

You can convert it back to degrees Celsius by subtracting 273.