Problem Relating Temperature and Thermal Energy

[chinnie15]

Homework Statement

An ideal gas is at 40°C. The gas is cooled, reducing the thermal energy by 35%. What is the new temperature in °C?

Homework Equations

I'm not sure there is one?

The Attempt at a Solution

Since, in an ideal gas, thermal energy is proportional to temperature, I multiplied 40°C by .35 and got a change of 14°C. After subtracting, I get a resulting temperature of 26°C. But, the online program is telling me this is incorrect? Am I doing something wrong?

Thanks!

 

[ehild]

Thermal energy of the ideal gas is proportional to the absolute temperature.

ehild

 

[chinnie15]

Ohh, ok. I got it now, thanks! :) The answer is -70C.