What are the Thermodynamic Processes for a Monoatomic Ideal Gas?

[lesodk]

Homework Statement

A Cyclic proces of three parts for a monoatomic idealgas:

1-2:
Isochor, where:
p2 = 2*p1
v2 = v1

2-3:
Adiabatic, from v2 = v3, where:
v3 > v2
p3 = p1

3-1:
unknow proces, where
v4 = v1
p4 = p1

My problem is to determine
Q1, Q2, Q3 and W1, W2, W3 and dU1, dU2, dU3

I can't find U3, W3

Homework Equations

dU1 + dU2 + dU3 = 0

W1 = 0, dU = Q (isochor)
Q2 = 0, dU = -W (adiabatic)

The Attempt at a Solution

I'm really lost on the part finding Q3, W3
:(

 

[Hootenanny]

Have you determined dU₁ and dU₂?

 

[lesodk]

yes i have

 

[Hootenanny]

And is the data plotted on a PV curve?

 

[lesodk]

Nope, i don't have that information.

 

[Hootenanny]

A Cyclic proces of three parts for a monoatomic idealgas:

1-2:
Isochor, where:
p2 = 2*p1
v2 = v1

2-3:
Adiabatic, from v2 = v3, where:
v3 > v2
p3 = p1

3-1:
unknow proces, where
v4 = v1
p4 = p1

Shouldn't these two values be v₃ and p₃?

 

[lesodk]

my point is just that after v3 and p3, you go back to the initial place v1 and p1.
Thats what i mean by 3-1.

 

[Hootenanny]

my point is just that after v3 and p3, you go back to the initial place v1 and p1.
Thats what i mean by 3-1.

Yes but note that p₃ = p₁, therefore this third 'unknown process' (3-1) is isobaric.