Electrochemistry

Which of the following statements is FALSE about electrolysis?

• nonspontaneous reaction

• chemical reaction to electrical

• Electrical energy is used

• electrical to chemical reaction

The half-reaction that occurs at the anode during the electrolysis of molten sodium bromide is?

• 2 Br^----> Br₂ + 2 e^-

• Br₂ + 2 e^- ---> 2 Br^-

• Na⁺ + e^-  ---> Na

• Na ---> Na⁺ + e^-

In an electrolytic cell the electrode at which the electrons enter the solution is called the ______ ; the chemical change that occurs at this electrode is called _______.

•  anode, oxidation

• anode, reduction

• cathode, oxidation

• cathode, reduction

Which is TRUE?

• I=Q X T

• T=Q X I

• Q= I X T

• None

In voltaic cells, the salt bridge is important to_______ .

• is not necessary in order for the cell to work

• acts as a mechanism to allow mechanical mixing of the solutions

• allows charge balance to be maintained in the cell

• drives free electrons from one half-cell to the other

Which of the following statements is(are) true for all voltaic (or galvanic) cells?

(I) Reduction occurs at the cathode

(II) The anode gains mass during discharge (note: this means operation of the cell.)

(III) The voltage is less than or equal to zero.

• only III

• II and III

• only II

• only I

In the standard notation for a voltaic cell, the double vertical line "||" represents

• a salt bridge

• gas electrode

• a wire (metal) connection

• a phase boundary

In the standard notation for a voltaic cell, the single vertical line "|" represents

• a salt bridge

• gas electrode

• a wire (metal) connection

• a phase boundary

As the cell given below operates, the strip of silver gains mass (only silver) and the concentration of silver ions in the solution around the silver strip decreases, while the strip of lead loses mass and the concentration of lead increases in the solution around the lead strip. Which of the following represents the reaction that occurs at the negative electrode in the above cell?
Pb / Pb(NO₃)₂ (1.0 M) || AgNO₃ (1.0 M) / Ag

•  Pb²⁺ + 2 e^-  ---> Pb

• Pb --->  Pb²⁺ + 2 e^-

• Ag⁺ + e^- ---> Ag

• Ag ---> Ag⁺ + e^-

E^ocell ( Standard Cell Potential)   – The potential measured at a specific temperature (298 K) with no current flowing and all concentrations in their “Standard States”. Which in False about “Standard States”?

• 1 M for solutions

• 1 atm for gases

• Pure solids for electrodes

• None