One mole of an ideal gas undergoes near- equilibrium expansion at a constant temperature of 300K. During this process, the volume of the gas changes from 1L to 3L. The gas constant, R
, is 8.314 Jmol
-1
K
-1
. Include units in your final answers.
a.
Calculate the work done by the system in this process. (1pt)
w = -nRTln(V2/V1)
w = -1*8.314*300*ln(3/1)
= -2740J
= -2.74kJ
b.
Calculate the heat transferred to the system in this process. (1pt)
w = -q
=> q = 2.74kJ
c.
What is the change in entropy of the system during this process? (1pt)
ΔS = q
rev
/T
=> ΔS = 2740J/300K = 9.1J K
-1
A system consists of 2 moles of an ideal gas in a piston. The gas is initially under high pressure, and when constraints on the piston are released the gas expands slowly, under isothermal and reversible conditions at 300K. The volume increases from 1 liter to 2 liters during the expansion.
The change in energy of the gas is zero, because it is an ideal gas. An ideal gas only has
kinetic energy, and the energy is constant under constant temperature.
.
