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 first 580 seconds?
A. 1.6 × 10−3
B. 1.9 × 10−3
C. 2.0 × 10−3
D. 2.2 × 10−3

Answer 1

Answer:

C. 2.0 x 10⁻³

Explanation:

The average rate of a reaction is the rate of change of the concentration of the reactants (or products) with time.

The average rate of the reaction = - (ΔC)/(Δt).

∵ The concentration of the reactants changes from 1.8 M to 0.6M for 580 s.

∴ The average rate of the reaction over the first 580 seconds

   = - (ΔC)/(Δt) = - [(0.6M) - (1.8 M)]/[(580.0 s) - (0.0 s)] = 2.0 x 10⁻³ M.s⁻¹.

So C. 2.0 x 10⁻³ is the right answer

Answer 2

Answer:

The average rate of reaction over the first 580 seconds is answer(C)

Explanation:

average rate = 1.8 M - 0.6 M/580 s - 0 s = 1.2 M/580 s  = 2.0 × 10−3 M/s