Comparing thermo dynamic processes

[icelated]

Homework Statement

in a cylinder, 1.2 mol of an ideal gas, gamma = 1.67 initially at 3.60 x10^5 pa
and 300k, is compressed until the volume is halved.

I need help with 1) c
and
2)

Compute work done on the gas if the compression is:

1)

a) isothermal
b) adiabatic
c) isobaric

2) in which case is the absolue value of the change in internal energy of the gas the greatest? least?

Homework Equations

I think i have a and b worked out.

The Attempt at a Solution

for c) would this be the correct approach?

is this part correct?

V1 = ?
V2 = 1/2V1

w = p(V2 - V1)
w = p(1/2v - v)

pv = nrt

w = -1/2nrt?

2) greatest is isobaric because?
least is isothermal because delta u =0 constant temp and temp is related to change in internal energy.

 

[SteamKing]

How can the gas get compressed if the process is isobaric? What other property must change?

 

[icelated]

the volume is being compressed. But, th pressure remains constant so the area of work is less than the other 2 processes? Adiabatic is the most?