Ch. 20/21 Exam

When an atom undergoes oxidation, what changes.

• the charge

• the atomic mass

• the number of neutrons

What is the general definition of Oxidation?

• The loss of electrons and a decrease of charge

• The loss of neutrons and a decrease of charge

• The loss of electrons and an increase in charge

What is the oxidation number of N in KNO3?

• +5

• -2

• +9

In a redox reaction, the number of electrons lost by the reducing agent is equal to what?

• equals the number of electrons gained by the oxidizing agent

• equals the number of electrons gained by the reducing agent

• equals the number of protons gained by the reducing agent

For the reaction X + Y → XY, the element that will be reduced is the one that is what?

• less electronegative

• more electronegative

• less reactive

In any electrochemical cell, the cathode is what type of electrode?

• Electrode at which some species gains electrons

• Electrode at which some species lose electrons

• Electrode at which some species gains neutrons

In a voltaic cell, what is the function of the salt bridge?

• Allows radioactivity to be maintained in the cell

• Allows the cathode and anode to make direct contact

• Allows charge balance to be maintained in the cell

The corrosion, or rusting, of iron is an example of a naturally occurring voltaic cell. To prevent corrosion, sacrificial anodes are sometimes attached to rust-susceptible iron. Sacrificial anodes must do what?

• gain electrons more easily than iron

• lose electrons more easily than iron

• lost neutron more easily than iron

A strip of metal X is immersed in a 1M solution of X ions. When this half-cell is connected to a standard  hydrogen electrode, a voltmeter reads a positive reduction potential. Which of the following is true of the X electrode?

• It accepts electrons more readily than H ions.

• It accepts electrons less readily than H ions.

• It accepts protons more readily than H ions.

To electroplate an iron fork with silver, what must happen?

• Electrical current must be applied to the iron fork

• Electrical current must pass around the fork

• An electrical current cannot be applied to the fork.