Consider two equilibrium thermodynamic states of an ideal gas. In state A. the g
ID: 2007753 • Letter: C
Question
Consider two equilibrium thermodynamic states of an ideal gas. In state A. the gas has volume 2 times 10 -3 m3 and pressure 3 times 10 5 pa and in state D, the gas has volume 6 times 10 -3 m3 and pressure 18 times 10 5 pa. Calculate the total work done by the gas when it is taken from state A to state D by a sequence of two processes, first an isobaric expansion to state B and then an isochoric pressure change from state B to state D. Calculate the total work done by the gas when it is taken from state A to state D by a different sequence of two process, first an isochoric pressure change to state C and then an isobaric expansion from state C to state DExplanation / Answer
a . A (3e5 , 2e-3 ) --- > B ( 18e5 , 6 e 3 ) ;
for the first change W = P integration ( dV ) ; since isobaric process ;
W = 3e5 ( 6e-3 - 2e-3) = 1200 ;
in the second case , W = 0 , since vloume change is zero ;
net work done = 1200 J ;
b. since first step is isochoric ,no work is done , since dV = 0 ;
in second case ,
( 3e5 , 2e-3 ) --> ( 18e5 , 2e-3 ) ---> ( 18e5 , 6e-3 ) ;
in the first step W = 0 ;
in the second step ,
W = 18e5 ( 6e-3 - 2e-3 ) = 7200 J < ------ ans