Electrochemistry

Question 1

Why is platinum used?

Answer 1

Provides a surface for the reaction

Question 2

What is a salt bridge?

Answer 2

U shaped tube that contains a salt solution to keep charges balanced

Question 3

Define standard cell potential

Answer 3

Voltage measured when half cell is connected to a standard hydrogen half cell under standard conditions

Question 4

What is EMF?

Answer 4

Potential difference between anode and cathode

Question 5

What is the calculation?

Answer 5

Substract more negative Ecell from more positive
Reduction at more positive (cathode)
Oxidation at more negative (anode)

Question 6

Describe feasibility

Answer 6

Cell potential > 0.4v
REDOX reaction only feasible if species that’s more positive is able to be reduced
Limitation - not standard conditions or reaction occurs too slowly it doesn’t appear to happen

Question 7

Describe reasoning

Answer 7

X has more -ive E so X redox Eq has greater tendency to lose electron and moves to left
X eqm releases electron into wire, flow to Y which gains electron and Eq moves to right

Question 8

What species acts as a more powerful oxidising agent?

Answer 8

More positive

Question 9

What makes Ecell smaller?

Answer 9

Ag+/Ag more positive

Question 10

Name two advantages of fuel cells and two disadvantages

Answer 10

Non-polluting
/greater efficiency
difficult to store
flammable