(21-11) Thermodynamics problem help

[qspartan570]

Homework Statement

The volume of a gas is decreased by a constant external pressure of 0.25 atm, changing from 2.0 liters to 0.50 liters. During this compression, 75 J of energy flows out of the gas. Find the work done by the gas and its change in internal energy.

Homework Equations

First Law of Thermodynamics= ΔE=Q - W

The Attempt at a Solution

Is 75 J of energy the final energy

I'm not too sure on how to find the Q or W

I'm not too sure on how to complete this problem

Could someone me help on how to start the problem

 

[Andrew Mason]

Homework Statement

The volume of a gas is decreased by a constant external pressure of 0.25 atm, changing from 2.0 liters to 0.50 liters. During this compression, 75 J of energy flows out of the gas. Find the work done by the gas and its change in internal energy.

Homework Equations

First Law of Thermodynamics= ΔE=Q - W

I think that we are to assume that the energy flows out of the gas in the form of heat flow, Q. I think we are also supposed to assume that the work done by the gas, W = PΔV. With those assumptions you should be able to solve this. Be careful about the sign of the work.

AM