# Thermodynamics processes

1. Apr 11, 2010

### urgent

1. The problem statement, all variables and given/known data

Three moles of an ideal monoatomic gas trebles its initial volume in an isobaric expansion from state A to state B. The gas is then cooled isochorically to state C and finally compressed isothermally until it returns to state A. The molar gas constant is R = 8.314 J mol–1 K–1 and Boltzmann's constant is 1.38 × 10–23 J K–1.

(a) If state B corresponds to a pressure P = 5 atm (1 atm = 1.013 × 10^5 Pa) and temperature T = 535 °C, determine the temperature of the gas in state A.

2. Relevant equations
unknown

3. The attempt at a solution

2. Apr 11, 2010

### Andrew Mason

First, determine the volume at B and then the pressure at C. (Hint: use ideal gas law. Be careful about temp. scale). With that, you can determine the temperature at C, which is the same as the temperature at A.

AM

3. Apr 12, 2010

### urgent

First, determine the volume at B and then the pressure at C. (Hint: use ideal gas law. Be careful about temp. scale). With that, you can determine the temperature at C, which is the same as the temperature at A.

AM

hi um i tried to do it as u advised, but i was not able to get the right answer, could you please state the suggested formulas to use in order? thanks

4. Apr 12, 2010

### Andrew Mason

Find the volume at B and the temperature at A (which is the same as temperature at C).:

PV=nRT.

At B: P = 5 atm = 5 x 101.3 KPa = 506.5 KPa; T = 535+273 = 808K. n = 3 moles

V = nRT/P = ________?

This is 3 times the volume at A, so the volume at A is _______. Applying the ideal gas law, the temperature at A is: _______

AM

5. Apr 14, 2010

### urgent

thx alot for ur help!! really appreciate it=]