Chemistry Practice Problems Average Rate of Reaction Practice Problems Solution: If the experiment below is run for 60 s, 0.16 mol ...

🤓 Based on our data, we think this question is relevant for Professor Tang's class at USF.

Solution: If the experiment below is run for 60 s, 0.16 mol A remain. Which of the following statements is or are true?After 60 s there are 0.84 mol B in the flask.The decrease in the number of moles of A from t1 = 0 to t2 = 20 s is greater than that for t1 = 40 to t2 = 60 s.The average rate for the reaction from t1 = 40 to t2 = 60 s is 7.0 10-3 M/s.

Problem

If the experiment below is run for 60 s, 0.16 mol A remain. Which of the following statements is or are true?

At time 0 seconds, a flask contains 1.00 mole of A and 0 moles of B. At 20 seconds, the flask holds 0.54 moles of A and 0.46 moles of B. At 40 seconds, the flask holds 0.3 moles of A and 0.7 moles of B.

  1. After 60 s there are 0.84 mol B in the flask.
  2. The decrease in the number of moles of A from t1 = 0 to t2 = 20 s is greater than that for t1 = 40 to t2 = 60 s.
  3. The average rate for the reaction from t1 = 40 to t2 = 60 s is 7.0 10-3 M/s.


Solution
  • Analyzing each statement, for Statement I: after 60 s there are 0.84 mol B in the flask

  • Checking the diagrams provided, each flask showed that sum of mole A and B, regardless of the time, will always be 1. Where at: 0s, moles A = 1 mol; 

20s, moles A = 0.54 moles and moles B = 0.46 moles (0.54 + 0.46 = 1)

40s, moles A = 0.30 moles and moles B = 0.70 moles (0.30 + 0.70 = 1)

  • Therefore, at 60s if A is 0.16 moles, then B must be 0.84 moles (1 - 0.16 = 0.84 moles)

 Statement I is true


Solution BlurView Complete Written Solution