Misc
Fuel cells require constant what to run?
Fuel
For the following half-reactions, how many electrons would be transferred in the balanced overall redox reaction:
Cr2+(aq)→Cr3+(aq) + e-
Br2(l) + 2e-→2Br-(aq)
2
A weak acid and its conjugate base or a weak base and its conjugate acid
Buffer
In order for a reduction reaction to occur, you must have what?
An oxidation reaction
Do you need a pH meter to use an indicator?
No
You can increase buffer capacity with increased...
concentration
Is required to balance the movement of the negative charges, thus preventing a charge imbalance that would stop the reaction
The background electrolyte
If you want to keep a solution at pH=7.2, what should the pKa be?
7.2
Oxidation is loss or gain of electrons?
LOSS
the use of electrical energy to drive a nonspontaneous chemical reaction
Electrolysis
The standard reduction potentials are in reference to what?
The SHE
The SHE (standard hydrogen electrode) has a E value of what?
The pKa for acetic acid is 4.75. If you have a solution containing 0.25 M acetate and 0.075 M acetic acid, what is its pH?
5.27
half-reaction for the reduction of iron(III) ion to iron
Fe3+(aq) + 3e-→Fe(s)
T/F: Some batteries can be recharged.
True
If you titrate a weak base with a strong acid, at the equivalence point, pH
<7
For the biochemical reaction 2NADH + 2H+ + O2→2NAD+ + 2H2O, 4 e- are transferred and E°cell=1.14 V. What is the value of DG° for the reaction?
-440,000J
The midpoint of the flattest part of the titration curve for a weak acid:
pH = pKa
Oxidation occurs at the _______
Anode
If E°=0.797 V for this half-reaction:
Hg2+(aq) + 2e-→Hg(l)
What is the value of E° for the following half-reaction:
3Hg2+(aq) + 6e-→3Hg(l)
0.797V
T/F: Very large or very small values of the equilibrium constant can be measured by measuring voltages
T
If 2Na(s) + I2(s) →2Na+(aq) + 2I-(aq) with E°cell=3.25 V, what is the value for Ecell if [Na+]=3.25 M and [I-]=2.42 M?
3.20V
In general, if you have a 1.00 M solution of acetic acid (which will be an equilibrium between acetic acid and acetate), and you add an equal volume of 1.00 M sodium acetate, what will happen to the pH of the solution? [Hint: there are no calculations needed to answer this question]
pH will increase
Given the following half-reactions, what will be the overall reaction and the value of E°cell?
Au3+(aq) + 3e-→Au(s) E°=1.50 V
Br2(l) +2e-→2Br-(aq) E°=1.09 V
2Au3+(aq) + 6Br-(aq)→2Au(s) + 3Br2(l) E°=0.41 V
What is the molar solubility of silver chloride in water, AgCl, Ksp=1.77X10-10?
1.33x10^-5M