The table shows the concentration of a reactant in the reaction mixture over a period of time.





Reactant Concentration

Time Concentration

0 s 1.8 M

210 s 1.2 M

450 s 0.8 M

580 s 0.6 M

720 s 0.4 M





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

1.7 × 10−3

1.9 × 10−3

2.0 × 10−3

2.2 × 10−3