Module 6

To calculate cell potential

1. Find the half reaction from the reduction potentials table 2. Substitute the half cell potential into the equation 3. use your answer to determine if the reaction is spontaneous or not. Positive cell potential will result in a spontaneous reaction. Negative is non spontanious

What are the main components of a voltaic cell? Describe each their roles in the operation of a cell.

1. the anode is the electrode where oxidation occurs 2. the cathode is the electrode where reduction occurs. 3. salt bridge is the chamber of electrolytes necessary to complete the circuit in a voltaic cell. Internal connection between cells that allows the movement of ions 4. External circuit (voltmeter) is used to conduct the flow of electrons between the electrodes of the voltaic cell and usually includes a switch 5. The oxidation and reduction reactions are separated into compounds called half reactions.

The process of using electricity to break apart substances. A type of electrochemical cell that uses electrically to force a nonspontaneous reaction

Electrolysis

______________ is a process where an electric current is used to plate a metal onto another surface.

Electroplating

what is the main purpose of electroplating metals

Electroplating is the process of plating one metal onto another by hydrolysis. Most commonly for decorative purposes or to prevent corrosion of metal. Specific types of electroplating such as copper plating , silver plating and chromium plating. Process that uses electric current to reduce dissolved metal cations so that they from a covent metal coating on electrode.

What factors can be varied to control the thickness of the plating effect.

Plating thickness is dependent on the cathode efficiency of a particular plating solution, that current density and the amount of plating time.

______ is one that occurs without any added energy. All reactions are spontaneous

Spontaneous reaction

The ____ is the electrode where reduction occurs . Electrons are ___ by positive ions at the surface of this electrode. It is normally labeled the positive electrode

cathode and reduction

electrochemical cell

consists of two half reactions connected by an external wire that will carry the electric current. two metals in the cell that serve as electrodes. The electrode where oxidation takes place is called the anode. The metal undergoing oxidation will lose electrons which will pass through the external wire to the other electrode. Electrode where reduction takes place is called the cathode. The force driving the electrons is called the EMF or electromotive force and is measured in volts.

Electrochemical cell

converts chemical energy into electrical energy from a spontaneous redox reaction

Flow of electrons

electric curent

______________ flow in the external circuit from the anode to the cathode of an electrochemical cell.

electrons

A spontaneous reaction is one that occurs without any added ______________

energy

Law of conservation of energy

energy cannot be created nor destroyed, it is simply converted from one form of energy to another.

Spontaneous reaction/rule states that any species on _____ hand side of the activity series (written as the reduction reactions) will react spontaneously. Spontaneous reactions are " up to the right?

left

Faradays Law

n = I ^t/ F n = moles of electrons I = current (amperes ^ t = seconds F - Faradays constant (96500)

For every redox reaction, the half reaction that is more ______ will proceed as the reduction reaction and the half reaction that is more _______ will proceed as an oxidation reaction

positive and negative

The stronger the oxidizing agent, the weaker the ______________ ability.

reducing

All the half reactions on the Table of Standard Reduction Potentials with Values are written as ______________.

reduction

To counter the accumulation of ions around the electrodes, there must be an internal connection between the cells that allows the movement of ions. This is called the ____. Is usually a glass tube filled with an ionic solution with porous material (cotton, glass, wood) plugging the ends. Allows ions to move slowly in and out of the tube.

salt bridge

The reaction in an electrochemical cell is always _______

spontaneous

Standard Reduction Potential table (EMF Eo)

used to determine the spontaneity and electrical potential of a given cell. Positive cell potential will result in a spontaneous reaction. Any negative cell potential will result in a non-spontaneous reaction

The general process of electroplating

Involves dipping an object that can conduct electricity into a solution that has dissolved metal in it. Objects are submerged into a solution connected by wires and a battery source. Anode becomes positively charged (from solution) and electrons flow through battery. Electrons move through cathode and the negative charge attracts the positively charged anode ion and sticks to become on with cathode, becomes neutral

Voltage

A unit of cell potential or electrical potential. the ability of an electrochemical cell to do electrical work, or its ability (force) to move electrons from one electrode to another

studied work on electrolytes. piled plates on top of one another. Discovered that electric current. First battery ever created

Alessandro Giuseppe Antoonio Anstasio Volta

The ____ is the electrode at which _____ occurs. Electrons are lost from this electrode. IT is normally labeled the negative electrode.

Anode and oxidation

Two methods for the calculation of Eo cell

E cell - Ex ox + red Ecell = Eo cell cathode - Anode

Michael Faraday

Discovered that the amount of product formed at each electrode is directly proportional to the amount the of electricity that passes through the cell. who coined the terms, electrode, anode, cathode, electrolyte ion, anion, cation.

The industrial form of a cell is _____. It is the major method of producing sodium metal and pure supplies of chlorine gas.

Downs cell

Cell potentital

For voltaic cell is a measure of the amount of energy that can be generated to drive an electric current though a wire

Discovered that muscle contractions result from electrical stimulation

Luigi Galvani

c

Many 'reference' electrodes were tried before one was chosen as the standard to which all other electrodes would be measured. Which half-cell was finally chosen as the reference? a. oxygen b. copper c. hydrogen d. zinc

In an electrochemical cell, the electrode at which reduction occurs is called the ______________.

cathode

d

Which of the following statements related to cell potential is false? a. The cell potential for a voltaic cell is a measure of the amount of voltage that can be generated by driving an electric current through a wire. b. One joule of energy is produced when one coulomb of electrical charge is transported across a potential of one volt. c. This difference in potential difference is an indication of how much energy is available to move electrons from the anode to the cathode. d. Electric charge can only flow between two electrodes when there is an equal amount of electric potential between the two points.

d

Which type of cell converts chemical energy into electrical energy from a spontaneous redox reaction? a. an electrolytic cell b. a half-cell c. a wet cell d. a voltaic cell

Which of the following components is not part of a voltaic cell? a. a battery b. two half-reaction cells c. an external wire d. the salt bridge

a

measure the rate at which the charge is transferred

ammeter

A short-hand notation is often used to represent the voltaic cell diagram. What does the double vertical line represent? a. It represents a phase boundary between the metal and the ion in solution. b. It represents the salt bridge. c. It represents the anode. d. It represents the cathode.

b

Which statement about an anode in a voltaic cell is false? a. The anode is the electrode at which oxidation occurs. b. The anode is the electrode at which reduction occurs. c. Electrons are lost from this electrode. d. It is normally labeled the negative electrode.

b