# Average Reaction Rates

1. Mar 26, 2017

### Not a Wrench

1. The problem statement, all variables and given/known data

2. Relevant equations
Δ[A]/aΔt = Δ[ B]/bΔt

3. The attempt at a solution
Δ[ I]/3Δt = Δ[H]/2Δt = 7.8E-4. What exactly am I supposed to do for this?

2. Mar 26, 2017

### Staff: Mentor

I don't understand what you calculate here, and the number you get there (which is not the answer) doesn't agree with the number you put into the form (which is also not the answer).

Part B works in the same way as part A.

3. Mar 26, 2017

### Not a Wrench

What I did in part A was divide 7.8E-4 by 3. However I am unsure what this is fundamentally doing apparently as I can not understand how to get part B. Do I divide 7.8E-4 by 2?

4. Mar 27, 2017

### mjc123

That is not true. -Δ[I-]/Δt = 7.8e-4 M/s (don't forget the units), as you were told. Given this, how would you apply Δ[ I-]/3Δt = Δ[H+]/2Δt to answer the question?

5. Mar 27, 2017

### Staff: Mentor

You know $I_3^-$ is produced at 2.6*10-4 M/s. For every molecule of $I_3^-$ produced, two atoms of $H^+$ are used.
What is the rate of $H^+$ consumption?