8/17/2019 Electricity and Chemical change

1/2

Name:

© OUP: this may be reproduced for class use solely for the purchaser’s institute

WORK SH E E T

8 Electricity and chemical changeCore curriculum

1 a  For A–J below, circle the letter if the bulb will light. Cross it out if the bulb will not light.

distilled water

DA

bulb

mercury

B

sodium chloride

solution

paraffin

C

molten lead

bromide

E

solid potassium

chloride

IF G H J

aluminium graphiteplastic diamond

b For the substances above where the bulb lights, which will decompose?

 

2 Which row shows the products at the anode and cathode, during electrolysis? Circle its letter.

at the anode at the cathode

A metals non-metals (except hydrogen)

B metals non-metals, including hydrogen

C non-metals, including hydrogen metals

D non-metals (except hydrogen) metals or hydrogen

3 Which row shows the products from the electrolysis of concentrated sodium chloride solution?

  Circle its letter.

positive electrode negative electrode

A hydrogen oxygen

B hydrogen chlorine

C oxygen hydrogen

D chlorine hydrogen

8/17/2019 Electricity and Chemical change

2/2

© OUP: this may be reproduced for class use solely for the purchaser’s institute

WORK SH E E T

Extended curriculum

4 Strontium chloride (SrCl2) is melted and electricity is passed through it, using inert electrodes.

Strontium is a reactive metal from Group II of the Periodic Table.

a Write ionic equations for the reactions at the electrodes:

  At the cathode (2):

At the anode (1):

b Name the three products obtained from the electrolysis of concentrated aqueous

strontium chloride.

 

5 The diagrams below are to show apparatus for purifying copper, by electrolysis.

a To diagram A:

i add a battery and wires to complete the circuit

ii mark 1 and 2 on the correct electrodes

impure

copper

A B

pure

copper

copper(II) sulfate

solution

b Complete diagram B to show when electrolysis is almost complete.

Mark in the battery, wires, electrodes, electrolyte, and impurities.

c Write the half-equation for the reaction:

i at the positive electrode

ii at the negative electrode

d Give one use of copper, that requires it to be very pure: