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 Home > JCEDLib > QBank > Collection > CQs and ChPs > CQs > Writing CQs >
Writing Conceptual Questions (CQs): Reversed Calculation Question
Reverse an algorithmic calculation by giving the answer and asking for an extrapolation from the answer.

Two example questions are given below.

Example 1
Original question: What is the mass of 0.52 mole of  F atoms?

Modified question: Which of the following could be the mass of one mole of atoms?

  1. 1.66 x 10-24 g
  2. 6.02 x 1023 g
  3. 0.100797 g
  4. 101.1 g
  5. None of these.

Example 2

Original question: The following data were obtained for the reaction

2 NO + O2   2 NO2

[NO], M  [O2], M  Initial rate, M s-1
1 x 10-3  1 x 10-3  2.0 x 10-5
2 x 10-3  1 x 10-3  8.0 x 10-5
3 x 10-3  1 x 10-3  18.0 x 10-5
2 x 10-3  2 x 10-3  16.0 x 10-5
2 x 10-3  3 x 10-3  24.0 x 10-5

Which is the correct rate law?

  1. Rate = k[NO][O2]
  2. Rate = k[NO][O2]2
  3. Rate = k[NO]2[O2]
  4. Rate = k[NO]2
  5. Rate = k[NO]2[O2]2

Modified question: Which will have no effect on the rate of the reaction

CO(g) + NO2(g)   CO2(g) + NO(g)

if the rate law for the reaction is Rate = k[NO2]2?

  1. Decreasing the pressure of NO2
  2. Increasing the concentration of CO
  3. Increasing the temperature
  4. Adding a catalyst
  5. All of these will effect the rate.

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