Unit 2 Exam

Question 1

Redox Reactions involve….

Answer 1

The transfer of electrons

Question 2

Oxidation

Answer 2

Loss of electrons

Question 3

Reduction

Answer 3

Gain of Electrons

Question 4

Oxidizing Agent

Answer 4

Thing being reduced

Question 5

Reducing Agent

Answer 5

Thing being oxidized

Question 6

What are the two types of Cells. Give a brief description

Answer 6

Voltaic (Galvanic)- Spontaneous, system does work on surroundings Anode (-) -> Cathode (+)
Electrolytic- nonspontaneous, energy comes from surroundings Anode (+) -> Cathode (-)

Question 7

Where does Oxidation occur?
Reduction?

Answer 7

Anode
Cathode

Question 8

What does the salt bridge do?

Answer 8

Prevents the buildup of electrons at the cathode and a lack of electrons at the anode

Question 9

Which has a higher reduction potential, the anode or the cathode?

Answer 9

Cathode

Question 10

Voltage

Answer 10

Potential energy, potential for electrons to flow

Question 11

Standard Hydrogen Electrode

Answer 11

Accepted Zero voltage
Not practical because of the release of H2 gas

Question 12

Indicator Electrode

Answer 12

Where the analyte is active, most likely the Cathode

Question 13

Reference electrode

Answer 13

Maintains a constant potential for relative voltage measurements by the indicator electrode
Anode

Question 14

Examples of reference electrodes

Answer 14

Copper in lab
Ag/AgCl electrode
Hydrogen electrode
Combination electrode
Saturate Calomel Ectectrode (S.C.E)

Question 15

Examples of indicator electrodes

Answer 15

Metal (wire, lead)
Ion selective (detecting only one ion)

Question 16

How does a pH indicator work

Answer 16

PH of internal solution is fixed, as the pH of the external solution changes, the electron potential across the glass changes

Question 17

How does an ion selective electrode work?

Answer 17

Unknown ion on outside, known on the inside, influx tells you the concentration

Question 18

How is the voltage and the flow of electrons related?

Answer 18

The bigger the voltage the better the flow of electrons

Question 19

Overpotential

Answer 19

Voltage required to overcome the activation energy for a reaction at an electrode surface

Question 20

Ohmic Potential

Answer 20

Voltage needed to overcome the inherent cell resistance

Question 21

Concentration Polarization

Answer 21

Occurs when the concentrations of reactants and products are different from those in bulk solution

Question 22

How does adding ions (salt) effect the resistance

Answer 22

By adding salt, you are increasing the ions and decreasing the resistance because the ions are passing on the charge