Quiz 2 material

[Robert Zellmer]

Quiz 2 will cover the following:

Chapter 14 (14.3-14.7), Chapter 15 (15.1-15.7)

There is some overlap with quiz 1 for chapter 14.


Section 14.3

Know how to obtain a rate from data and how to use rate data to 
determine the
rate law using the method of initial rates. This is shown in the book in
sample ex 14.6 (and the practice exercise) and my notes. You really need to
learn how to do this using the second example I used in lecture (the long
one). If you don't you will have problems with some of the end-of-chapter
exercises (especially the last one for section 14.3).

Remember, rate laws can depend on concentration of reactants, products and
catalysts. The orders of substances in the rate law can be whole numbers,
simple fractions, negative (usually seen for products and inhibitors). 
To get
the overall order you simply add the orders for everything in the rate law.
Also, remember in general you can't write the rate law from the balanced
chemical equation. It must be determined experimentally. The ONLY time 
you can
write a rate law from a balanced eqn is if you know the reaction is an
elementary reaction (a single-step mechanism) and you don't know this by
simply looking at the reaction.

Section 14.4

Know what an integrated rate equation is for zero-order, 1st-order and
2nd-order reactions and be able to use them. Know what the half-life is for
zero-order, 1st-order and 2nd-order reactions. This is in section 14.4. The
equations for zero-order are in the notes and there are a couple of 
questions
in the chapter 14 handouts passed out in class and on the web (see "notes"
link) about zero and 2nd order. Be able to do the special problem passed 
out
in class and sent via e-mail.

Section 14.5:

Understand the relationship between temp., activation energy (Ea) and rate
constant (Arrhenus eqn.) and the rate of the reaction.  Understand how all
this relates to collision theory and transition state theory.

Section 14.6:

Understand mechanisms and how to obtain a rate law from a mechanism,
rate laws for elementary reactions, recognize intermediates,
and what molecularity means.

Remember, steps in a mechanism are always written as elementary processes,
which means the rate law for a step can be written from the balanced eqn
for that step.  This is the ONLY time you can write the rate law from a
balanced eqn.

Section 14.7:

Know what catalysts are and the four common characteristics of catalysts,
homogeneous and heterogeneous catalysis, how catalysts work and be able
to recognize a substance as a catalyst or intermediate in a mechanism. Know
how a catalyst affects rate and how this can be seen using the Arrhenus 
eqn.

You can find the handouts mentioned above at

*Chapter 14 - Chemical Kinetics - Handouts* 
<http://www.chemistry.ohio-state.edu/%7Erzellmer/chem1220/notes/ch14houts.pdf> 


You should be able do to homework problems 14.9-14.16, 14.53-14.96,
14.110-14.118, 14.120-14.126

For those of you using the 11th edition the quiz covers sections 14.5-14.7
and homework problems 14.7-14.12, 14.47-14.82, 14.94-14.103, 14.105-14.111

For those of you using the 10th edition the quiz covers sections 14.5-14.7
and homework problems 14.6-14.10, 14.45-14.80, 14.90-14.97, 14.99-14.105

Don't forget the extra homework problems handed out in class. They can also
be found on the web at the Notes link (see above) or Homework link where 
you
will also find the solutions,

*CH 14 - Kinetics, Extra Problems and Solutions* 
<http://www.chemistry.ohio-state.edu/%7Erzellmer/chem1220/homewk/ch14hmwk_add.pdf>


Sections 15.1-15.6:

You need to understand how to set up an expression for the equilibrium
constant, K and how to use it.  Understand how to set up K for
heterogeneous equilibria (when you have pure solids and liquids involved
in the equilibrium).  What appears in an equilibrium constant (gases and
solutes in solution but not pure solids or liquids)?

What does the magnitude of K tell you?  Does the reaction go to completion
and by how much (mostly products or "essentially only" products)? Does the
reaction "not occur to any great extent" and how little reaction occurs
(mostly reactants or "essentially only" reactants)?  Are there appreciable
amounts of reactants and products at equilibrium?

Remember K depends on the form of the balanced equation and you can
relate the K for one form of the balanced equation to another
(e.g. K_rev = 1/K_for or K_for^-1).
Know the relationship between equilibrium constants when you add several
balanced equations to get a new balanced equation.

Know how to use an equilibrium (ICE) table and use it to determine K from
equilibrium concentrations.

Know how to relate Kp and Kc.

Understand the reaction quotient, Q, and how you use it with K to predict
whether the reaction is at equilibrium or not and if not which direction
does it proceed to reach equilibrium.

Know how to use an ICE table to calculate equilibrium conc. starting with
initial conc. and the equilibrium constant, K.

On the quiz, if you need to use an ICE table, you MUST SHOW the WORK and 
the
ICE table.  When making any assumptions you should show that your
assumptions are okay (less than 5% error).  If the percent error is greater
than 5%, you need to solve the problem in a more exacting way (solve a
quadratic, method of successive approximations, etc.).  You
must show this work.  If you don't, you will not get full credit.

Section 15.7: Le Chatelier's Principle

Understand how changing conc. shifts a reaction
(AWAY from ADDED, TOWARD REMOVED).  Remember adding or
removing (small amounts, but not all) of a pure solid or pure liquid will
not shift a reaction.  Removing all of a pure solid or pure liquid will 
shift the
reaction (toward the removed substance - you have to have some of the
solid or liquid to be at equilibrium when they are present in the rxn).
Adding or removing a pure liquid which is also the solvent will cause a
shift due to an indirect effect (e.g. adding solvent decreases the conc. of
the solutes causing the reaction to shift).  I discussed this using exp 
5 (EQL)
in lecture today.  Conc. changes do NOT affect the numerical value of K.

Know how changing pressure (due to volume changes) effects a reaction.
Increasing pressure (by reducing the volume) shifts the reaction toward
fewer moles of gase.  Decreasing pressure (by inc. the volume) shifts
the reaction toward more moles of gas.
Pressure changes do NOT affect the numerical value of K.

Also, know how changing temperature shifts a reaction AND changes the 
numerical
value of the equilibrium constant, K (changing conc. and pressures do 
not affect
the numerical value of K).

You should be able do to homework problems 15.1-15.100

For those of you using the 11th edition the quiz covers sections 
15.1-15.7 and
homework problems 15.1-15.88

For those of you using the 10th edition the quiz covers sections 
15.1-15.7 and
homework problems 15.1-15.85


Don't forget the extra homework problems.  They can be found on the web at
the Homework link on the class web page (CH 15 - Extra ICE Table 
Problems and
Solutions),

*CH 15 - Extra ICE Table Problems and Solutions* 
<http://www.chemistry.ohio-state.edu/%7Erzellmer/chem1220/homewk/ch15_extra_problems.pdf>


Dr. Zellmer
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