quiz 4

The rate constant for a reaction is determined to be 7.51 x 10-7 s-1 at 25 °C, and 8.72 x 10-2 s-1 at 125 °C. What is the activation energy for this reaction? Question 10 options: 115 kJ/mol 3.03 kJ/mol 16.9 kJ/mol 13.8 kJ/mol

115 kJ/mol

The rate constant for a reaction determined to be 2.74 x 103 s-1 at 115 °C, and the activation energy is 46 kJ/mol. What is the frequency factor for this reaction? Question 9 options: 4.25 x 109 s-1 2.78 x 103 s-1 6.45 x 10-7 s-1 2.15 x 1024 s-1

4.25 x 109 s-1

What does the red arrow represent? Question 3 options: Change in temperature Enthalpy plus activation energy Activation energy Enthalpy

Activation energy

According to the Arrhenius equation Question 4 options: higher activation energy will produce a higher rate constant for a reaction higher temperature will produce a higher rate constant for a reaction lower temperature will produce a higher activation energy for a reaction higher frequency factor will produce a lower activation energy for a reaction

higher temperature will produce a higher rate constant for a reaction

Which of the following is true of about reaction mechanisms? Question 5 options: The rate-limiting step is the slowest step in a reaction mechanism The molecularity of a reaction is the number of intermediate steps in a reaction A reaction mechanism is the same as the balanced chemical equation Elementary reactions produce unstable transition states

The rate-limiting step is the slowest step in a reaction mechanism

A transition state is Question 2 options: a stable chemical species produced in one step of a reaction, and then consumed in a subsequent step an unstable species created by the collision and combination of two reactant molecules always formed when two reactants collide easily detectable in laboratory experiments

an unstable species created by the collision and combination of two reactant molecules

The elementary reaction CH3 + Cl ⟶ CH3Cl is an example of a Question 6 options: tetramolecular reaction termolecular reaction bimolecular reaction unimolecular reaction

bimolecular reaction

A heterogeneous catalyst Question 8 options: typically reacts to form an intermediate substance before being regenerated in a subsequent reaction step. is present in a different phase than the reactants can be present in any phase is present in the same phase as the reactants

is present in a different phase than the reactants

A catalyst Question 7 options: is never a reactant in the reaction it catalyzes lowers the activation energy of a reaction must be present in the same phase as the reactants is consumed during an overall reaction

lowers the activation energy of a reaction

According to collision theory Question 1 options: the reacting species must collide with enough energy to combine nuclei more collisions between reactant molecules lead to slower reaction rates a reaction will occur anytime two reactants collide reaction rates will increase as concentration of the reactants increases

reaction rates will increase as concentration of the reactants increases