Chemistry Pressure to Energy.

Question

Calculate the internal energy (in Joules) of a system that loses 174.0 J that is compressed with a pressure of 3.77 atm from 13.51 L to 1.00 L.

Answer 1

∆U = q + w

∆U = Internal energy = ?

q = heat = -174.0 J (negative b/c the system LOSES heat)

w = work = -P∆V (pressure-volume work) = -(3.77 atm)(1.00 - 13.51 L)

w = -3.77 atm * -12.51 L

w = 47.16 Latm

Converting this to joules, we have 47.16 Latm x 101.325 J / 1 Latm = 4778 J (positive b/c work is being

done ON the system (compression).

∆U = q + w = -174.0 J + 4778 J

∆U = 4604 J = 4.60 kJ