Electrochem

Question 1

In a standard cell representation, where does the most negative half cell go?

Answer 1

Half cell with most negative potential goes on the left

Question 2

What is the standard hydrogen electrode used for?

Answer 2

Measuring the electrode potential of half cells

Question 3

What is the cell potential of the standard hydrogen electrode?

Answer 3

0V

Question 4

What are the standard conditions needed when measuring half cell potential with standard hydrogen electrode?

Answer 4

1.0 mol dm^3 solution of H+
298K
100kPa

Question 5

What does the hydrogen electrode consists of?

Answer 5

HCl
Hydrogen gas
Platinum electrode

Question 6

Why is a platinum electrode used in a half cell?

Answer 6

Metallic so conducts electricity but is also inert so wont react with acid

Question 7

What is a salt bridge used for?

Answer 7

Transfer ions between solution

Question 8

What factors can alter the electrode potential of a half cell?

Answer 8

Temp
Conc of ions
Pressure

Question 9

In an electrode, what reaction occurs at the most negative electrode?

Answer 9

Oxidation

Question 10

In an electrode, what reaction occurs at the most positive electrode?

Answer 10

Reduction

Question 11

How do you calculate EMF?

Answer 11

Emf(R) – Emf(L)

Question 12

In the electrochemical series, which half reaction contains the best oxidising agent and which contains the best reducing agent?

Answer 12

Oxidising - Most positive one

Reducing - most negative one

Question 13

When combing the half equations for an electrode, which equation should you flip?

Answer 13

The most negative one

Question 14

What are the standard conditions of an electrode?

Answer 14

1.0 mol dm^3 of each solution for each ion solution
298K
100kPa

Question 15

What is the start of the standard cell representation for a hydrogen electrode>

Answer 15

Pt / H+(aq) / H2(g)//

Question 16

What can standard electrode potentials be used for?

Answer 16

Determining the feasibility of a redox reaction

Question 17

What is the value of the EMF is the reaction is feasible?

Answer 17

Positive

Question 18

How will an increasew in conc affect emf?

Answer 18

Make it more positive

Question 19

How will an increase in pressure affect emf?

Answer 19

Make it more negative

Question 20

What are the 3 types of electrochemical cells?

Answer 20

Rechargeable
Non rechargeable
Fuel cells

Question 21

What type of reaction occurs in a rechargeable cell?

Answer 21

Reversible

Question 22

What do lithium ion cells consists of?

Answer 22

Lithium cobalt oxide electrode
Graphite electrode
Lithium salt in organic solvent

Question 23

What reaction occurs at the negative electrode in a lithium ion cell

Answer 23

Li –> Li+ + e-

Question 24

What reaction occurs at the positive electrode in a lithium ion cell?

Answer 24

e- + Li+ + CoO2 –> Li^+[CoO2]^-

Question 25

How is a lithium ion cell recharged?

Answer 25

A current is applied over the cell to force the electrons in the other direction

Question 26

What is a fuel cell?

Answer 26

An electrochemical cell that does not need recharging

Question 27

What is required in a hydrogen fuel cell?

Answer 27

Continuous supply of hydrogen and oxygen to generate a continuous current

Question 28

What reaction occurs at the anode (+) in the hydrogen fuel cell?

Answer 28

H2 + 2OH- —> 2H2O + 2e-

Question 29

What reaction occurs at the cathode (-) in the hydrogen fuel cell?

Answer 29

O2 + 2H2O + 4e- —> 4OH-

Question 30

Benefit of using a hydrogen fuel cell?

Answer 30

Produces water as a waste product so seen as environmentally friendly

Question 31

Drawback of using hydrogen fuel cells?

Answer 31

Use highly flammable hydrogen Expensive to produce