What are the units of k for the rate law: Rate = k[A]2[B]2, when the concentration unit is mol/L?
A. s-1
B. L mol-1 s-1
C. L2 mol-2 s-1
D. L3 mol-3 s-1
A reaction has the following stoichiometry:
H2 + 2 ICl ---> I2 + 2 HCl
Which of the following would be a correct definition of the rate?
A. Rate = +Δ[H2]/Δt
B. Rate = +Δ[HCl]/Δt
C. Rate = -Δ[ICl]/Δt
D. Rate = +(1/2)Δ[HCl]/Δt
1.
units of rate = molL-1s-1
Units of concentration = molL-1
Hence for a general nth order reaction units of K = Units of rate / [units of concentration]n
n = order of the reaction
Hence Units of K = molL-1s-1 /[molL-1]n
Rate = K [A]2[B]2
overall order of the reaction = 2 + 2 = 4
Hence Units of K = molL-1s-1 /[molL-1]4 = L3 mol-3 s-1
Hence option (D) is correct annswer.
2.
Rate of a general reaction xA -------> yB is given as:
Rate of reaction = - 1/x[Rate of change of concentration of A] = + 1/y[rate of change of concentration of B]
- sign indicates concentration of reactants decreaseand
+ sign indicates the concentration of products increases
Hence potion (D) +(1/2)Δ[HCl]/Δ is the correct answer.
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