Core Practical 10 = Setting Up An Electrochemical Cell

Question 1

What should we do to the electrodes first before using them?

Answer 1

Clean any metal oxide from surface using sand paper
Remove any grease using cotton wool soaked in propanone

Question 2

What beakers are we using?

Answer 2

100cm3 ones with 50cm3 of 1moldm-3 of solution of ions

Question 3

How do we make a salt bridge?

Answer 3

Using A rope soaked in SATURATED potassium nitrate solution

Question 5

How to connect the 2 half cells at the electrodes?

Answer 5

Use 2 crocodile clips clipped to electrode
Connected to a high resistance voltmeter

Question 6

Why do we use a salt bridge?

Answer 6

To complete the circuit so the salt can balance the charges in each half cell

Question 7

How to decide what solution to soak the salt bridge in?

Answer 7

One that will not react with solutions or electrodes

Question 8

Why not use wire to connect the 2 half cells instead of a salt bridge?

Answer 8

Because a wire will form its own electrode system with solutions: ie, make elements give up electrons

Question 9

What if we are using gas and solution or 2 solutions?

Answer 9

Use a platinum electrode which is inert, does not react with solution but provides a surface for the oxidation/reduction to occur on