Exam 18: Electrochemistry: The Quest for Clean Energy

You have a job as a summer intern in an orange juice processing plant. Part of your job is to determine the amount of vitamin C in a given quantity of orange juice. To make this determination, you titrate the orange juice with I₃^, the triiodide ion. To make sure you know what you are doing, your supervisor asks you how many electrons are transferred in the reaction. The reaction describing the titration is given below. What is your response? ascorbate dehydroascorbate  2H^  3I^

A voltaic cell is constructed based on the oxidation of zinc metal and the reduction of silver cations. Solutions of silver nitrate and zinc nitrate also were used. Locate the zinc nitrate on the diagram.

For the following electrochemical cell, draw and label a diagram representing the components of the voltaic cell. Al(s)|Al^3(aq) (0.50 M )||Ni^2(aq) (0.30 M )|Ni(s)

Based on the information in the table of standard reduction potentials below, what is the standard cell potential for an electrochemical cell that has iron, Fe, and magnesium, Mg, electrodes? Also, identify the cathode. Standard Reduction Potentials (volts) in Aqueous Solution 1.80 1.50 0.771 0.535 0.124 1.66 2.37 2.93

The unit of current, ampere (A), is defined as ________

Where in the periodic table do you find the elements that typically do not participate in redox processes?

A hydrogen fuel cell depends on ________

The oxidation of methanol, as described by the equation below, has a G value of 937.9 kJ/mol. What is the standard cell potential for a methanol fuel cell?

The Nernst equation can be used to calculate ________

For the following electrochemical cell, write the cell diagram using standard notation.

Permanganate ion can oxidize sulfite in basic solution according to the following equation. The relevant standard reduction potentials are 0.59 V for the manganese compound and 0.92 V for the sulfur compound. Determine the cell potential for the reaction at 298 K with the concentrations in the table. Species Concentration MnO₄^0.250 M SO₃^20.356 M SO₄^20.278 M OH^0.0222 M

Cadmium is a toxic heavy metal. The U.S. Environmental Protection Agency limits the concentration of cadmium ions in drinking water to less than 4  10^8 M. Assess the feasibility of monitoring of cadmium in drinking water using a voltaic cell based on the following half-reactions. E  0.7996 V E  0.4030 V If the silver ion concentration were 0.100 M, what cadmium ion concentration at 298 K would increase the cell potential by 10 mV from the standard cell potential?

Which one of the following statements about the recharging of a voltaic cell is not correct? When a voltaic cell is recharged, it is run as an electrolytic cell.

The unit of electrical power, watt (W), is defined as ________

The electrodes on batteries are labeled  and . The ________ is labeled ________, and ________ occurs there.

From the following table of standard reduction potentials, identify the best oxidizing and reducing agents. Also, determine the species from the table that is(are) capable of oxidizing iron to iron(III). Standard Reduction Potentials (volts) in Aqueous Solution 1.80 1.50 0.771 0.535 0.124 1.66 2.37 2.93

Which cell diagram is correct for this electrochemical cell?

What is the mass of copper used if it was oxidized to copper(II) over 35s, given the average electrical current delivered was 200 A?

A NiMH battery uses ________ as the oxidizing agent.

Using the following data, determine the standard cell potential for the electrochemical cell constructed using the following reaction, where zinc is the anode and lead is the cathode. Half-reaction Standard Reduction Potential (V) 0.34 1.66