Electrochemistry

Question 1

Is the oxidant (oxidising agent) being reduced or oxidised?

Answer 1

reduced

Question 2

Is the reductant (reducing agent) being reduced or oxidised?

Answer 2

oxidised

Question 3

What is water’s polarity and what intermolecular forces does it have?

Answer 3

very polar and a permanent dipole

Question 4

When are electrochemical curves obtained?

Answer 4

when electrolysis causes a NET chemical reaction

Question 5

What is electrochemistry?

Answer 5

ionic conduction in an electrolyte solution that is coupled to electronic conduction in a solid

Question 6

Why is water a very polar molcule?

Answer 6

As oxygen is very electronegative and hydrogen is very electropositive. The oxygen has a small negative charge and the hydrogens have a small positive charge.

Question 7

Reduction occurs at the….

Answer 7

Cathode

Question 8

Oxidation occurs at the….

Answer 8

Anode

Question 9

At what state does an electrochemical cell need to be to measure voltages?

Answer 9

A voltemeter measures voltages between two identical phases not at equilibrium

Question 10

What is the cell voltage?

Answer 10

sum of several potential differences

Question 11

Is the anode positive or negative in a galvanic cell?

Answer 11

negative

Question 12

Is the cathode positive or negative in a galvanic cell?

Answer 12

positive

Question 13

What is the cathode made of in a dry cell battery?

Answer 13

The cathode is a graphite rod surrounded by a mix of carbon paste and MnO2.

Question 14

What is the anode made of in a dry cell battery?

Answer 14

the anode is zinc metal. MnO2 (manganese dioxide) is the electroactive material and carbon powder is just added to make it electrically conductive

Question 15

What is the electrolyte in a dry cell battery?

Answer 15

The electrolyte is an aqueous solution of ZnCl2 and NH4Cl adsorbed on a some sort of inert felt pad

Question 16

What happens when there are electrodes that are the same material, with different concentrations, which one will be an anode or the cathode?

Answer 16

The higher concentration will be a cathode.

The lower concentration will be an anode

Question 17

What happens when there are electrodes that are the same material, with different concentrations?

Answer 17

Solution with higher concentration will deposit metal on electrode
Electrode in lower concentrated solution will corrode

Question 18

When will electron transfer (voltage) cease?

Answer 18

when both sides have the same concentration

Question 19

What is the anode in the lead-acid cell made of?

Answer 19

Made of spongy lead packed into a lead grid at the anode,

Question 20

What is the cathode in the lead-acid cell made of?

Answer 20

red-brown lead(IV) oxide (PbO2) packed into a lead grid at the cathode and dlite sulfuric acid with about 35% H2SO4, by mass.

Question 21

What is the equation for the water equation in corrosion?

Answer 21

2 H2O + 2 e -> H2(g)

2OH−(aq)

Question 22

What is the equation for the oxygen equation in corrosion?

Answer 22

O2(g) + 4H+(aq) + 4e −> 2 H2O

Question 23

What is the equation for corrosion in moist air?

Answer 23

O2(g) + 2H2O + 4e− 4OH−