Electrolysis

Question 1

What is the overall equation of Manganate oxide and dichromate ions

Answer 1

2MnO4- + 16H+ + 5C2O4 2- → 2Mn2+ + 10CO2 + 8H2O

Question 2

Why use high resistance voltmeter?

Answer 2

Stop current from flowing in circuit. (measure maximum p.d.)

Question 3

What molecule is salt bridge made out of?

Answer 3

Potassium Nitrate

Question 4

Why can’t wire or potassium chloride used as salt bridge

Answer 4

wire: set up its own electrode system with the solutions

KCl: can form complexes with copper ions

Question 5

Positive electrode is always….

Answer 5

Reduction (electrons gained, used up)

Question 6

Negative electrode is always….

Answer 6

Oxidation (electrons lost, give off)

Question 7

3 Components for a standard hydrogen electrode

Answer 7

➼ Pressure at 100kPa
➼ Solution at 1 mol dm–3
➼ Temperature at 298K

Question 8

Which direction does negative electrode travel (oxidation)

Answer 8

right to left

Question 9

Which direction does positive electrode travel (reduction)

Answer 9

left to right

Question 10

As emf become positive, what happens

Answer 10

strong oxidation agents on left side of equation

Question 11

AS emf becomes negative, what happens

Answer 11

strong reducing agent on right side of equation

Question 12

What happens when increasing concentration on reactants

Answer 12

emf increases

Question 13

What is the equation for Hydrogen fuel cell

Answer 13

1. 4e- + 4H2O 2H2

Question 13

What is the equation for Hydrogen fuel cell

Answer 13

1. 4e- + 4H2O 2H2

Question 13

What are the equations for Hydrogen fuel cell

Answer 13

4e- + 4H2O → 2H2 + 4OH-

4e- + 2H2O + O2 → 4OH-

Overall: 2H2 + O2 → 2H2O