Assignment:
Q1. Given the following information, which of the statements is true?
Cu2+(aq) + e- → Cu+(aq) Eº = 0.34V
2 H+(aq) + 2 e- → H2(g) Eº = 0.0V
Fe2+(aq) + 2 e- → Fe(s) Eº = - 0.44V
Ni(s) → Ni2+(aq) + 2 e- Eº = 0.25V
a) Cu+2(aq) is the strongest oxidizing agent
b) Cu+2(aq) is the weakest oxidizing agent
c) Ni(s) is the strongest oxidizing agent
d) Fe(s) would be the weakest reducing agent
e) H+(aq) would be the strongest oxidizing agent
Q2. A galvanic electrochemical cell has the overall reaction:
Mg(s) + Pb2+(aq) → Mg2+(aq) + Pb(s)
Which of the following statements is FALSE?
a) The mass of the Mg electrode will decrease.
b) Negative ions from the salt bridge will flow to the chamber with the Mg electrode.
c) Electrons in the external circuit will flow from the Pb electrode to the Mg electrode.
d) The concentration of Mg2+ will increase.
e) The cell reaction will be spontaneous.
Q3. The portion of a pH electrode that develops a potential when exposed to hydrogen ions is
a) a glass membrane with cavities designed to hold H+ that are moving through a concentration gradient .
b) a drop of liquid mercury that undergoes a redox reaction with a mercury salt .
c) a silver wire that is oxidized to Ag+ in the presence of H+.
d) a plastic polymer membrane that allows diffusion of H+ across the membrane.
e) a crystal of a Li+ salt that reduces to Li when exposed to H+.
Q4. The path that excitation radiation travels in a single-beam UV-visible spectrophotometer is
a) source → sample → wavelength selector → detector
b) source → wavelength selector → sample → detector
c) source → wavelength selector → detector
d) source → sample → detector → wavelength selector
e) source → wavelength selector → sample → wavelength selector → detector
Q5. The most common mechanism of separation used in chromatography is:
a) ion exchange
b) affinity
c) partition
d) molecular exclusion
Q6. Surface adsorption is a form of coprecipitation phenomena in which
a) an impurity sticks to the precipitate surface by electrostatic attraction.
b) one type of ion in the crystal lattice of the precipitate is replaced by another type of ion that has a similar size.
c) the precipitate is heated and trapped as a gas.
d) an impurity is trapped inside of the growing precipitate crystals.
e) an impurity precipitates on top of a previously formed precipitate.
Q7. Qualitative analysis is best defined as
a) identification of an analyte in a sample.
b) determination of the mass of a sample.
c) determination of the analyte concentration in a sample.
d) taking a representative sample from a bulk quantity.
e) separation of analytes in a sample.