I have 3 probs I'm working on, not really sure how to go about these... 1) A gas, while expanding under isobaric conditions, does 611 J of work. The pressure of the gas is 1.70 x 10^5 Pa, and its initial volume is 1.30 x 10^-3 m^3. What is the final volume of the gas? I'm assuming I would use the equation: W=P delta V=P(Vfinal-Vinitial) but since I don't know the final volume how do I go about solving this problem? 2) Suppose 5.50 moles of a monatomic ideal gas expands adiabatically and its temperature decreases from 425 to 218 K. Determine (a) the work done (including the algebraic sign) by the gas, and (b) the change in its internal energy. I thought that the correct way to go about this was to use W=3/2 nR(Tinitial-Tfinal) and I ended up with an answer of 7731.45 J for the first part of the problem but the program says it's wrong. How do I solve parts A and B? 3) One-half a mole of a monatomic ideal gas expands adiabatically and does 909 J of work. By how much does its temperature change in Kelvin? Use the proper sign to specify whether the change is an increase or a decrease. For this prob I thought I could use the same equation as in #2 and I ended up with an answer of 24.34 but this sounds wrong. What should I do here?