another physics problem

[mlee]

Hi people,

Who can help me solve this problem?

One mole of an ideal monatomic gas at STP first undergoes an isothermal expansion so that the volume at point b is 2.5times the volume of point a. Next, the heat is extracted at a constant volume so that the pressure drops. The gas is then compressed adiabatically back to the original state.
Question a:
Calcultate the pressures at point b and point c

Question b:
Determine the temperature at point c

Question c:
Determine the work done, heat input or extracted, and the change in entropy for each process.

Question d:
What is the efficiency of this cycle>?

Question e:
WHat is the change in entropy 'delta s' for one complete cycle a->b->c->a? Explain your reasoning

Question f:
In which part of the cycle does the entropy, S, show the greatest decrease? Explain your reasoning


Many thanxxx