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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: chimia12 on November 19, 2020, 05:54:25 PM

Title: Question in Enthalpy
Post by: chimia12 on November 19, 2020, 05:54:25 PM

Hi,
I need help with some question.
 What I tried:
https://ibb.co/0MnG16g

The question:
6 mol of ideal gas trapped in a system closed by a piston which is fixed by brakes as shown in the drawing. The system consists of thermal contact with the environment. At a certain moment the brakes are released and the system is allowed to expand to double the volume. The external pressure is 4 times smaller than the final pressure in the system. Calculate the heat that alternates between the system and the environment (in calories) if it is given that the ambient temperature is 349 degrees Celsius.

The drawing:
https://ibb.co/H2dBXwG

Title: Re: Question in Enthalpy
Post by: mjc123 on November 20, 2020, 06:46:56 AM

Careful with units. What value of R did you use?
The answer at the end of line 1 is 306 L atm, not 306 J. You will probably find it easier to work with R = 8.314 J/mol/K.
Otherwise your method looks right, but your answer is wrong.