Chapter 9 and 22 Vocab

1. %%Rate of Reaction%%- a measure of the rate at which reactants are used up or the rate at which products are formed; the units of rate are mol*/((dm^3)s), rate = (change in amount of reactants/products)/ (time).

2. %%Collision Theory%%- In order to react w/ e/o, particles must collide in the correct orientation and w/ sufficient energy, the particles may be atoms, ions, or molecules.

3. %%Activation Energy%%- the minimum energy that colliding particles must possess for successful collision that results in a reaction to take place, denoted E[subscript a].

4. %%Catalyst%%- A substance that increases the rate of a reaction but remains chemically unchanged itself at the end of the reaction.

5. %%Boltzmann Distribution%%- A graph showing the distribution of energies of the particles in a sample at a given temperature.

6. %%Enzyme%%- A protein molecule that is a biological catalyst; most act on a specific substrate.

7. %%Substrate%%- A molecule that fits into the active site of an enzyme and reacts.

   (Chapter 22 begins)

8. %%Rate constant%%- The proportionality constant in the rate equation, denoted k.

9. %%Rate Equation%%- An equation showing the relationship between the rate constant and the concentration of those reactants that affect the rate of reaction; the general form of the equation is: rate=k([A]^m)([B]^n) where k is the rate constant, [A] and [B] are the concentrations of those reactants that affect the rate of reaction, m is the order of the reaction w/ respect to A and n is the order of reaction w/ respect to B.

   10. %%Order of Reaction%%- The power to which the concentration of a reactant is raised in the rate equation; if the concentration does not affect the rate, the reaction is zero order; if the rate is directly proportional to the reactant concentration, the reaction is first order; if the rate is directly proportional to the square of the reactant concentration, the reaction is second order.
   11. %%Half Life (t[subscript 1/2])%%- The time taken for the amount (or concentration) of the limiting reactant in a reaction to decrease to half its value.
   12. %%Rate Determining Step%%- The slowest step in a reaction mechanism.
   13. %%Homogeneous Catalyst%%- The type of catalysis in which the catalyst and reactants are in the same phase; for example, sulfuric acid catalyzing the formation of an ester from an alcohol and carboxylic acid (both reactants liquid).
   14. %%Heterogeneous Catalyst%%- The type of catalysis in which the catalyst is in a different phase from the reactants, for example, iron in the Haber process.
   15. %%Adsorption (in catalysis)%%- The first stage in heterogeneous catalysis; molecules of reactants (usually gases) form bonds with atoms on the surface of the catalyst.
   16. %%Desorption%%- The last stage in heterogeneous catalysis; the bonds holding the molecule(s) of product(s) to the surface of the catalyst are broken and the product molecules diffuse away from the surface of the catalyst.
   17. %%Instantaneous Rate of Change%%- The rate of reaction at any particular point in time.

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