Question

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 entire course of the reaction?
A. 1.6 × 10−3
B. 1.9 × 10−3
C. 2.0 × 10−3
D. 2.2 × 10−3

Answer 1

I have no idea why the other answer is only 1 star, it is 2.0 × 10^−3.

Explanation:

I just took the test and got it correct.

Answer 2

Option C

The average rate of the reaction over the entire course of the reaction is:
`2.0 * 10^(-3)`

Solution:

Average rate is the ratio of concentration change to the time taken for the change

`Average\ rate = ( \triangle c )/(\triangle t )`

The concentration of the reactants changes 1.8 M to 0.6 M

here, the time interval given is 0 to 580 sec

Therefore,

`Average\ rate = (1.8-0.6)/(580) \\\\Average\ rate = (1.2)/(580) \\\\Average\ rate \approx 2.0 * 10^(-3)`

Thus option C is correct