Question

the table shows the concentration of a reactant in the reaction mixture over a period of time. what is the average rate of the reaction over the first 450 seconds?

Answer 1

The question is missing the table. Here is the complete question.

The tableshows the concentration of a reactant in the mixture over a period of time.

Reactant Concentration

Time (s)         Concentration (M)

    0                       1.8

  210                      1.2

 450                      0.8

 580                      0.6

 720                      0.4

What is the average rate of reaction over the first 450 seconds?

A. 1.6x$10^{-3}$ M

B. 1.9x$10^{-3}$ M

C. 2.0x$10^{-3}$ M

D. 2.2x$10^{-3}$ M

Answer: D. 2.2x$10^{-3}$ M

Explanation: The average rate of a reaction is the rate of change of the concentrations (of reactants or products) in a period of time:

average = - ΔC/Δt

In this case, concentration is negative because it's related to reactant, since its concentration dimishes while the concentration of product increases.

For the first 450 seconds:

Average = $\frac{-(0.8 - 1.8)}{450 - 0}$

Average = $\frac{1}{450}$

Average = 0.0022

or

Average = 2.2x$10^{-3}$

So, the Average Rate of the reaction is 2.2x$10^{-3}$M