CHM 2046C Module 9: Chapter 15 Key Terms
Part K:
Key Terms Chapter 15
Fill in the blanks with the chapter 15 key
terms:
1. __________________ is the minimum energy that must be added to the
reaction for a reaction to occur; on a reaction coordinate diagram, it
corresponds to the energy required to go from the reactants up to the highest
point in the energy diagram.
2. __________________ An unstable species found in an effective collision
of reactants that exists momentarily when the system is highest in energy and
that can either form products or re-form reactants.
3. __________________ An equation that relates the rate constant,
temperature, and energy of activation:
K = A∙e-Ea/RT (Taylor’s version: K =
f∙o∙e-Ea/RT∙t)
4. __________________ The rate over a period of time; this is calculated
by taking two points on the concentration vs. time graph and dividing the
change in concentration by the change in time.
5. __________________ A term used to describe the elementary step involving two molecules (or ions, atoms, or free radicals).
6. __________________ A material that speeds up the reaction without being
permanently changed in the reaction.
7. __________________ The study of the rates of chemical reactions
8. __________________ A theory of
chemical reaction rates that proposes that reactant molecules must collide with
each other in order to react and that the molecules must collide with proper
orientation and with sufficient energy.
9. __________________ An individual step in a reaction mechanism.
10. __________________ A biological catalyst
11. __________________ The rate of the reaction depends on the
concentration of this reactant raised to the first power, [A]1 , or the rate of the reaction varies directly with a
change in concentration of this reactant..
12. __________________ The time required for the concentration of a
reactant to decrease to half its initial value.
13. __________________ A catalyst that is present in a different phase from
the reacting substances.
14. __________________ A catalyst that is present in the same phase as the
reacting substances.
15. __________________ the instantaneous reaction rate at the start of a
reaction.
16. __________________ the rate at a particular time: this is calculated by
calculating the slope of the line tangent to the concentration vs. time
graph at this time.
17. __________________ An equation that relates the concentration and time;
this equation is derived from the rate law using integral calculus.
18. __________________ a material that is produced in one step of a
mechanism but is consumed in a later step.
19. __________________ the number of reactant molecules (or ions, atoms, or
free radicals) involved in an elementary step.
20. __________________ the exponent to which a reactant’s concentration is
raised in the rate law.
21. __________________ the proportionality constant in the rate equation.
22. __________________ The slowest step in a reaction mechanism and therefore the step that limits the
overall reaction.
23. __________________ the mathematical relationship between reactant
concentrations and the reaction rate.
24. __________________ The change in concentration of a substance divided
by the change in time; if the material is a reactant, we must change the sign
of this calculation
25. __________________ the sequence of bond-making and bond-breaking steps
that occur during the conversion of reactants to products during a chemical
reaction.
26. __________________: A diagram of which the y-axis is energy (or
enthalpy) and the x-axis is a measure of the reaction’s progress.
27. __________________ the rate of the reaction depends on the
concentration of this reactant raised to the second power [A]2
28. __________________ a term used to describe an elementary step involving
three molecules (or ions, atoms, or free radicals); These steps are vary rare (
a three body collision).
29. __________________ the sum of the exponents in a rate equation.
30. __________________ the chemical species present at the maximum in
energy in a reaction coordinate diagram: it consists of atoms in some
intermediate state of bond breaking and bond formation.
31. __________________ A term used to describe the elementary step
involving only one molecule (*or ion, atom, or free radical).
32. __________________ the rate of the reaction does not depend on the
concentration of this reactant [A]0