Determine ΔE, Q and W for the data in the Table

[Northbysouth]

Homework Statement

The following table gives data, in KJ, for a system undergoing a power cycle consisting of four processes in series. Determine the a) missing table entries, each in KJ, and b) the thermal efficiency.

I have attached an image of the Table.

Homework Equations

Q = (E₂-E₁) + W

Q = ΔE + W

The Attempt at a Solution

I'm unsure whether a previous process affects the process that comes after it. Is it sufficient to use the formula that I've given to calculate the ΔE and W for processes 1-2, 3-4 and 4-1? If so, then how do I find the ΔE and W for process 2-3? Do I need to look at the process preceding it?

Would I be right in saying that:
W = 1200 for proces 1-2
ΔE = 0 for process 3-4
Q = 1000 for process 4-1

 

[Chestermiller]

Homework Statement

The following table gives data, in KJ, for a system undergoing a power cycle consisting of four processes in series. Determine the a) missing table entries, each in KJ, and b) the thermal efficiency.

I have attached an image of the Table.

Homework Equations

Q = (E₂-E₁) + W

Q = ΔE + W

The Attempt at a Solution

I'm unsure whether a previous process affects the process that comes after it. Is it sufficient to use the formula that I've given to calculate the ΔE and W for processes 1-2, 3-4 and 4-1? If so, then how do I find the ΔE and W for process 2-3? Do I need to look at the process preceding it?

Would I be right in saying that:
W = 1200 for proces 1-2
ΔE = 0 for process 3-4
Q = 1000 for process 4-1

The same formula applies to all 4 processes
If it's cyclic, the sum of all four ΔE's must be zero.

You were correct about the following:
W = 1200 for proces 1-2
ΔE = 0 for process 3-4

But, you were wrong about Q = 1000 for process 4-1. Check your arithmetic.

Since you know ΔE for 3 out of the four processes, you know it for the 4th because the sum of the ΔE's must be zero.