A container of 1.2 mol of an ideal gas has a volume of 5.4 L = 5.4 x 10 -3 m 3 .

ID: 1886348 • Letter: A

Question

A container of 1.2 mol of an ideal gas has a volume of 5.4 L = 5.4 x 10-3 m3. The gas is at an initial temperature of 350oK.

a) What is the initial pressure of the gas?

b) The gas is compressed until it reaches a final volume of 3.1 L while the pressure remains constant. What is the final temperature of the gas?

c) What is the magnitude of the change in thermal energy of the gas? Has the thermal energy increased or decreased? Explain your reasoning.

d) What is the magnitude of the energy transferred as work? Does the work transfer energy into or out of the gas? Explain your reasoning.

e) What is the magnitude of the energy transferred as heat? Does the heat transfer energy into or out of the gas? Explain your reasoning.

given

n = 1.2 mol
V = 5.4*10^-3 m^3
T = 350 K

a) use P*V = n*R*T

P = n*R*T/V

= 1.2*8.314*350/(5.4*10^-3)

= 6.5*10^5 Pa

b) at constant P, V/T = constant

V2/T2 = V1/T1

T2 = (V2/V1)*T1

= (3.1/5.4)*350

= 201 K

c) |delta_U| = |n*R*dT|

= |1.2*8.314*(350 - 201)|

= 1486 J

thermal energy is decreased. Because, temeperature is decreased.

d) magnitude of Workdone = P*delta_V

= 6.5*10^5*(5.4 - 3.1)*10^-3

= 1495 J

the work transfer energy out of the gas. Because, energy released by the gas to the surroundings.

use, Q = W + dU

= -1495 + (-1486)

= -2981

|Q| = 2981 J

the heat transfer energy out of the gas.

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.