Heat in the amount of 7.5 kJ is added to a closed system while its internal energy decreases by 12 kJ. How much energy is transferred as work? For a process causing the same change of state but for which the work is zero, how much heat is transferred?

Question

Brandon Cooley

Engineering

12 December, 06:03

Heat in the amount of 7.5 kJ is added to a closed system while its internal energy decreases by 12 kJ. How much energy is transferred as work? For a process causing the same change of state but for which the work is zero, how much heat is transferred?

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Answers (1)

Know the Answer?

Precious Reid · Answer 1

W = 19.5 KJ

Q = - 12 KJ

Explanation:

Given that

Heat added to the system, Q = 7.5 KJ

Change in the internal energy,ΔU = - 12 KJ

Lets take work done in this process = W

We know that

Q = ΔU + W

Now by putting the values in the above equation

7.5 = - 12 + W

W = 7.5 + 12 KJ

W = 19.5 KJ

If the work done is zero.

W = 0 KJ

Q = - 12 KJ + 0 KJ

Q = - 12 KJ

negative sign indicates that heat is rejected by the system.