Chapter 22- Electrochemistry

Question 1

Electrochemical Cell

Answer 1

Made up of two half cells. Each half cell is made up of a conductor (aka electrode) immersed in a electrolyte solution.

Produce electrical energy

Example: Daniel’s cell, or Galvanic cell

Question 2

Salt bridge

Answer 2

In an electrochemical cell, allows ions to be passed between the two electrodes without the transfer of the electrolyte solutions.

Typically a tube filled with potassium chloride, or a third electrolyte solution.

Question 3

In order for a voltage to be produced in an electrochemical cell…

Answer 3

Oxidation in one half cell and reduction in the other must occur simultaneously in order to produce a voltage.

Question 4

Ionic atmosphere

Answer 4

Surrounds each ion, reducing its velocity and reactivity. Contributes to cell activity, or effective concentration.

Question 5

Activity

Answer 5

“Effective concentration”

Solutions may behave as if they are of a lower concentration than they are in reality, due to the ionic atmosphere.

Used rather than molar concentration in electrochemistry.

Question 6

Activity coefficient

Answer 6

accounts for the difference between the effective concentration, and actual concentration of a solution.

a=Y[X]

where:
a=activity
Y=activity coefficient
[X]=concentration

Question 7

Hydration radius

Answer 7

Refers to the size of the ion when the hydrated sphere is included.

Question 8

Ionic strength

Answer 8

Refers to the strength of the electric field in a solution.

As ionic strength increases, the activity coefficient of a cell will decrease (gets closer to zero).

Question 9

Ion charge

Answer 9

As the ion charge increases, the activity coefficient will decrease.

Question 10

Ion size

Answer 10

The smaller the hydrated radius, the more important the activity effects become. (less ionic atmosphere means the solution will behave in a way that more accurately reflects its concentration)

Question 11

Potential difference

Answer 11

The difference in electrical potentials between two points. Allows work to be done.

Work is done when a charge carrier (electron) is moved through a potential difference.

Question 12

Potentiometry

Answer 12

Analytical technique that allows analyte concentration to be determined by measuring the potential difference within an electrochemical cell.