Developing Metals 4: Electrochemical Cell

Question 1

What do electrochemical cells do

Answer 1

Make electricity

Question 2

Describe how an electrochemical cell is made

Answer 2

• 2 different metal ms dipped in salt solutions of their own ions
• connected by a wire ( external circuit )

Question 3

How many reactions take place with an electrochemical cell and what are they

Answer 3

• 2 reactions
• Oxidation & Reduction
• = redox process

Question 4

Describe what happens in a zinc/copper electrochemical cell

Answer 4

• Zinc half cell

= Zn oxidised -> Zn2+ ion
= electrons that Zn looses are released into external circuit

• Copper half cell

= Cu takes ( gains ) electrons from external circuit
= Cu2+ reduced -> Cu

Question 5

Be able to draw fully labeled diagram for zinc/ copper electrochemical cell

Answer 5

Look at notes
Need - salt bridge
- high resistance voltmeter

Question 6

What is the purpose of a salt bridge in an electrochemical cell

Answer 6

• allows electrons to flow

- ensures the 2 halves remain electrically neutral

Question 7

What is the purpose of a high resistance voltmeter in an electrochemical cell

Answer 7

• negligible current flows

Question 8

In what direction do electrons flow through the wire in an electrochemical cell

Answer 8

Most reactive metal —> least reactive

Question 9

What does a voltmeter measure in an electrochemical cell

Answer 9

• Potential difference = voltage between the 2 half cells

= difference between the standard electrode potential of each half of the cells ( usually given these values )