Heat of 30 kcal is supplied to a system and 4200j of external work is done on the system so that it's volume decreases at constant pressure.what is the change in its internal energy (J=4200 j/kcal)
The answer is 1.302 x 10^-5
To find the change in internal energy of the system, we need to use the first law of thermodynamics, which states that the change in internal energy of a system is equal to the heat supplied to the system minus the work done by the system.
Given:
Heat supplied (Q) = 30 kcal
External work done (W) = 4200 J
J = 4200 J/kcal
First, let's convert the heat supplied from kcal to joules:
1 kcal = 4184 J
So, Q = 30 kcal * 4184 J/kcal = 125,520 J
Now, we can calculate the change in internal energy (ΔU):
ΔU = Q - W
Substituting the values:
ΔU = 125,520 J - 4200 J
= 121,320 J
Thus, the change in internal energy is 121,320 J.