Chemistry 1B

Spring 2008

Topics for Quiz 3

I.  Electrochemistry (Chapter 17)

            Balancing Redox equations

Oxidation, reduction, oxidizing agent, reducing agent

Galvanic cells, drawing cell components and flows

Cell potential, E^o (emf)

Calculating cell potentials

Relationship between  K, DG^o, E^o and spontaneous reactions

  DG^o = -n F E^o  (be able to use this equation, you don’t have to memorize it)

II.  Nuclear Chemistry (Chapter 18)

a, b, and g decay, b⁺ emission, electron capture, fission

Using the following equations (you need not memorize these equations):

            DN/Dt = -kN               N(t) = N_oe^-kt                 t_½= 0.693/k

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Chemistry 1B                                                                           Name _________________

Spring 2007

Quiz 3

This quiz has 3 pages, none of them blank.  Closed book and notes.  Please turn your cell phone all the way off.  Show all work.

5.

      (Hint:  these reactions are not in any special order.)

a)  Define oxidation:

b)  Define oxidizing agent:

c)  Which is the strongest oxidizing agent on the list shown above?

d)  Can Cr³⁺ oxidize Ag(s) to Ag⁺(aq)?

3.  The figure below shows a sketch of a voltaic cell:

a)      Identify the two half reactions.

b)      Determine E^o for this cell.

c)      Identify the anode and the cathode.

d)      Show the direction of electron flow and ion flow.

4.                  The emf (E_cell) for the cell in problem 3 can be increased by:

(circle all that apply:)

a.       Increasing [Ni²⁺]

b.      Increasing [Fe²⁺]

c.       Using a larger piece of Ni

d.      Using a larger piece of Fe

e.       Adding water.

Explain your logic.

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Chem 220                                                                                Name______________

Spring 1998

                                                                         Quiz 1

1. Radium was first discovered and isolated by Marie and Pierre Curie.  They purified the element from pitchblende ore; there is about 1g of radium in 7 tons of pitchblende.  The predominant isotope is ²²⁶Ra.  A 0.200g sample of ²²⁶Ra decays at the rate of 7.4 x 10⁹ disintegrations per second.  Write an equation for the a decay of ²²⁶Ra.  What is the half life of ²²⁶Ra?

2. Below is a picture of some ¹¹¹Ag atoms in a box.  ¹¹¹Ag decays by b decay, with a half life of 7.5 days.  Draw a picture of what the box contents will look like 1.0 day from now.

today  tomorrow

3.                  If 18.0% of a sample of zinc-65 decays in 69.9 days, what is the half-life of this isotope (in days?)