Aim for FiveChemistry

Short free-response question

A mixture of helium and argon

  • Unit 3
  • 4 points
  • About 9 minutes

You can use a calculator on this question, just like on exam day.

A shorter multipart question that sticks to one or two topics. Each part usually asks for one calculation, claim or explanation. On the exam: 4 questions (Questions 4–7), part of the 1-hour-45-minute free-response section; calculator allowed.

The question

A rigid 5.00 L container holds 0.200 mol of He(g) and 0.100 mol of Ar(g) at 300. K.

Suggested time: 9 minutes

Your answers are saved in this browser as you type.

Part (a)

1 point

Calculate the partial pressure of Ar(g) in the container, in atm.

0 / 2,500 characters

Part (b)

1 point

Compare the average kinetic energy of the He atoms with the average kinetic energy of the Ar atoms. Justify your answer.

0 / 2,500 characters

Part (c)

1 point

Describe the graph you would draw to show the Maxwell–Boltzmann distributions of speeds for He and Ar in this container on the same set of axes. Include what is plotted on each axis and how the two curves differ, and justify the difference.

0 / 2,500 characters

Part (d)

1 point

At very high pressure, which gas would deviate more from ideal behavior, He or Ar? Justify your answer.

0 / 2,500 characters

Checking scoring…

Scoring it yourself shows you the rubric, examples and a model answer. Try writing your answer first.