Question

Calculate the change in internal energy (?E) for a system that is giving off 25.0 kJ of heat and is changing from 12.00 L to 6.00 L in volume at 1.50 atm pressure. (Remember that 101.3 J = 1 L·atm)
13)
______
A)
+25.9 kJ
B)
937 kJ
C)
-24.1 kJ
D)
-16.0 kJ
E)
-25.9 kJ

Answer 1

first law of thermodynamics states that

(heat in - heat out ) + (work in -work out ) =change in internal energy of the system

hence 0-25000 + 1.5*101.3 (12-6)-0 =chage in internal energy

hence change in internal energy =24.08 KJ=24.1 KJ

here change in internal energy = final internal energy - initial internal energy

hence initial internal energy-final internal energy= -24.1 kJ