General Chemistry Ch 5. Chemical Kinetics

Question 1

Gibbs Free Energy

Answer 1

Determines whether or not a reaction is spontaneous

Question 2

Chemical mechanisms

Answer 2

Propose a series of steps that make up the overall reaction

Question 3

Intermediates

Answer 3

Molecules that exist within the course of a reaction but are neither reactants nor products overall

Question 4

Rate-determining step

Answer 4

Limits the maximum rate at which the reaction can proceed, the slowest step

Question 5

Collision theory

Answer 5

States that a reaction rate is proportional to the number of effective collisions between the reacting molecules

Question 6

Activation energy

Answer 6

Proper orientation and sufficient Kinect energy must be there for a collision to be effective

Question 7

Arrhenius equation

Answer 7

Mathematical way of representing collision theory

Question 8

Transition state theory

Answer 8

States that molecules from a transition state or activated complex during a reaction in which the old bonds are partially dissociated and the new bonds are partially formed

Question 9

Transition state

Answer 9

Highest point on a free energy reaction diagram, the reaction can proceed toward products or revert back to reactants

Question 10

Activated complex

Answer 10

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Question 11

Increasing reactant concentration reaction rate

Answer 11

Will increase reaction rate (except for zero-order reactions) because there are more effective collisions per time

Question 12

Increasing temperature reaction rate

Answer 12

Will increase the temperature because the particles kinetic energy is increased

Question 13

Changing the medium reaction rate

Answer 13

Can either increase or decrease the reaction rate depending on how the reactants interact with the medium

Question 14

Adding a catalyst reaction rate

Answer 14

Increases reaction rate because it lowers the activation energy, can either be homogeneous or heterogeneous

Question 15

Homogeneous catalysts

Answer 15

In the same phase as the reactants

Question 16

Heterogeneous catalysts

Answer 16

In a different phase than the reactants

Question 17

Reaction rate measurements

Answer 17

Measured in terms of the rate of disappearance of a reactant or appearance of a product

Question 18

Rate laws

Answer 18

Take the form of rate = k[A]^x[B]^y, must be determined from experimental data

Question 19

Rate orders

Answer 19

Do not usually match the stoichiometric coefficients, the sum of all individual rate orders in the rate law

Question 20

Zero order reactions

Answer 20

Have a constant rate that does not depend on the concentration of the reactant, rate can be changed only by changing the temp or adding a catalyst, concentration vs time curve is a straight line with a slope that equals -k

Question 21

First order reactions

Answer 21

Have a non constant rate that depends on the concentration of reactant, concentration vs time curve is nonlinear, slope of ln[A] vs time is -k

Question 22

Second order reactions

Answer 22

Have a non constant rate that depends on the concentration of reactant, concentration vs time curve is nonlinear, slop of 1/[A] vs time is k

Question 23

Broken-order reactions

Answer 23

Those with noninteger orders

Question 24

Mixed-order reactions

Answer 24

Those that have a rate order that changes over time