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5/35 MCQs for:

Reaction Kinetics

Consider a termolecular reaction of the type

A + 2B → products.

The units of the rate constant for the reaction is:

dm⁶ mol⁻² s⁻¹.

dm⁹ mol⁻³ s⁻¹.

mol dm⁻³ s⁻¹.

dm⁶ mol⁻² s⁻².

Which of the following statements is true about reaction order and molecularity?

Order of reaction and molecularity can be obtained from a balanced equation.

Order of reaction is equal molecularity.

Order of reaction is equal to molecularity when all species in the slow step of the reaction mechanism are considered.

Order of reaction is equal to molecularity when all species in the fast step of the reaction mechanism are considered.

For the reaction:

X₂ + Y + Z → XY + XZ

It is found that halving the concentration of X2 reduces the reaction rate by a factor of 0.5, tripling the concentration of Y, the reaction rate increases by a factor of 9 and doubling the concentration of Z, has no effect on the rate. The rate law for this reaction is:

R = K[X₂][Y].

R = K[X₂][Y]²[Z].

R = K[X₂][Y]³.

R = K[X₂][Y]².

At a particular temperature, two gases, A (represented by circles) and B (represented by squares), react to form products. The following molecular scenes represent starting mixtures for four experiments run at the same volume, labeled 1 through 4, with their initial rates (in mol L⁻¹s⁻¹):

The predicted initial rate of experiment 4 is:

R = 4.0 x 10⁻⁴ mol L⁻¹s⁻¹.

R = 4.0 x 10⁻⁴.

R = 2.0 x 10⁻⁴ mol L⁻¹s⁻¹.

R = 4.0 x 10⁴ mol L⁻¹s⁻¹.

For any chemical reaction to occur:

Collision energy must be greater than or equal the activation energy for the reaction.

Collision energy must be greater than the activation energy for the reaction.

Collision energy must be equal to the activation energy for the reaction.

Collision energy must be less than or equal the activation energy for the reaction.