14.1.2 - Electrochemical cells

Question 1

What is a salt bridge?

Answer 1

It makes an electrical connection between 2 halves of the cell allowing ions to flow

Question 2

What is a salt bridge usually made from?

Answer 2

Filter paper soaked in potassium nitrate

Question 3

What does a high resistance voltmeter measure?

Answer 3

The maximum potential difference across the cell

Question 4

What is the potential difference in an electrochemical cell a measure of?

Answer 4

How much an eletrode is tending to release of gain electrons

Question 5

In a chemical cell with copper sulfate and zinc, what is the more negative half cell?

Answer 5

Zinc
It loses electrons to form a positive ion so there is a large negative charge on this electrode.

Question 6

How can an equilibrium be established at an electrode in an electrochemical half cell?

Answer 6

When a metal loses electrons they remain on the surface of the metal.
Some positive ions will be attracted and be reduced.
Eventually the rate of ions leaving the metal to go into solution will be the same as those leaving the solution to go to the metal

Question 7

What does the salt bridge prevent?

Answer 7

The solutions from mixing

Question 8

What can be said about the reactivity of a metal and the negative charge of the electrode

Answer 8

A more reactive metal will lose electrons more easily.
These electrons will remain on the surface of the electrode making it more negative.