- #1
Philip Wong
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Homework Statement
Two moles of an ideal monoatomic gas trebles its initial volume is an isobraic expansion from state A to state B. The gas is then cooled ischorically to state C and finally compressed isothermally until it returns to state A.
The molar gas constat is: R = 8.314 J mol^-1 K^-1.
Boltzmann's constant: 1.38*10^-23JK^-1
state B temperature = 803K
state A temperature = 268K
What is the work done on the surroundings in each of the following processes:
(i) A > B
(ii) B > C
(iii) C > A
Homework Equations
(i)W= (intergration)n.R.T/V.dv
= n.R.T(B).(intergration) 1/V. dv
= n.R.T(A).ln(V(B)/V(A))
(ii) W = 0
(iii) W=n.R.(T(B)-T(A))
The Attempt at a Solution
(i) W = n.R.T(A).ln(V(B)/V(A))
=2*8.341*268*ln(2) = 3099J (which was wrong... correct answer should be 8900)
(ii) W= 0 as there is no work needed for cooling of the system
(iii) W=n.R.(T(A)-T(B))
2*8.341*(268-803) = -8924 (which was wrong... correct answer should be -4890)
can anyone tell me where did i do wrong?
thanks!