Electrodes

Question 1

What is a salt bridge

Answer 1

E.g. filter paper soaked in KNO3

It allows ions to flow between half cells and balance out the charges

Question 2

What must you do to the metal electrodes before you set up a cell

Answer 2

Clean them by rubbing them in emery paper and clean of any grease/oil using propanone

Question 3

Why is platinum used

Answer 3

It is inert and conducts electricity

Question 4

What is EMF

Answer 4

Electromotive force is the difference between to half cells in an electrochemical cell

Question 5

Example of non-rechargeable cell

Answer 5

Zinc-carbon dry cell battery

Zinc positive electrode
Maganese dioxide and carbon negative electrode
Ammonium chloride as paste inbetween acts as electrolyte

Question 6

Example of a rechargeable cell

Answer 6

Lithium cell

Lithium cobalt oxide electrode
Graphite electode

or NiCad or Lead-acid

Question 7

What are the electrodes made from in an oxygen-hydrogen fuel cell

Answer 7

Porous ceramic with a thin layer of platinum

Question 8

What electrolyte is used in a oxygen-hydrogen fuel cell

Answer 8

KOH in alkaline

Question 9

Why can rechargeable batteries be recharged

Answer 9

They are reversible reactions, so a current can be supplied to force the electrons to flow in the opposite direction around the circuit

Question 10

What is a standard electrode potential

Answer 10

The voltage measured under standard conditions when a half cell is connected to the standard hydrogen electrode3