8 original questions from New Regents. The worksheet, answer key, and browser practice are free.

Download worksheet PDFDownload worked answer keyPractice these questions online
Concentration Changes at Equilibrium 4 questions

Concentration Changes at Equilibrium

New Regents original practice • Name: ____________________ Date: __________ Show your work for written answers.

In the models below, the reversible reaction A + B ⇌ C is initially at equilibrium. Use the written equation to identify which direction consumes or produces each substance.

Question 1

If A is added at constant volume and temperature, which direction tends to consume some of the added A?

  1. The forward direction
  2. The reverse direction
  3. Neither direction can consume A.
  4. Both directions consume A.

Question 2

Some C is removed from a system at equilibrium. Explain which direction can replenish some C.

Write your answer and work on the printable worksheet, or answer online.

Question 3

Which change tends to favor the reverse direction in this model?

  1. Add A.
  2. Add B.
  3. Add C.
  4. Remove C.

Question 4

Explain how the forward and reverse rates compare once the disturbed system reaches a new equilibrium.

Write your answer and work on the printable worksheet, or answer online.

Answer this set online →

Recording a Concentration Disturbance 4 questions

Recording a Concentration Disturbance

Use the information below to answer the questions.

A simulation changes one substance at constant temperature and volume. Each run starts at the same equilibrium. The table gives the rates at which C particles form in the forward reaction and are consumed in the reverse reaction immediately after the change.

RunChangeForward rate (particles/min)Reverse rate (particles/min)
PAdd A128
QAdd C813
RRemove B48

Question 5

In which runs does the net change immediately favor the reverse reaction?

  1. P only
  2. P and Q
  3. Q and R
  4. All three

Question 6

Calculate the net rate of C production in run P immediately after the change. Use the two listed rates.

Write your answer and work on the printable worksheet, or answer online.

Question 7

Use run R’s rates to explain why some B can be produced after B is removed.

Write your answer and work on the printable worksheet, or answer online.

Question 8

Which condition identifies a new equilibrium in Q?

  1. C returns to exactly its original amount.
  2. Both rates become zero.
  3. Forward and reverse rates become equal.
  4. The amount of C becomes equal to the amount of A.

Answer this set online →

2025 Chemistry Reference Tables · Browse Chemistry worksheets