You are given the copper strip, lead strip, iron strip, aluminium strip, magnesium strip and copper (II) sulphate solution. Referring to the statement above, plan a laboratory experiment to construct the electrochemical series of the potential differences using different pairs of metals. Your planning must include the following items:

(a) Problem statement(b) All variables involved(c) Statement of hypothesis(d) List of materials and apparatus(e) Experimental procedure(f) Tabulation of data

Answer:

Problem statement:

How can the electrochemical series be constructed based on the potential difference between two metal?

Variables: Manipulated variable: Pairs of metalResponding variable: Potential difference / Voltmeter reading Fixed variable: Concentration and volume of copper (II) sulphate

Statement of hypothesis

The further apart the metal in the electrochemical series, the greater is their potential difference

List of materials and apparatus:

Materials: Copper strip, lead strip, iron strip, aluminium strip, magnesium strip and copper (II) sulphate solution, sandpaperApparatus: Voltmeter, beaker, connecting wire

Experimental procedure:

1. Clean the metals with sandpaper2. Pour 50 cm3 of copper(II)sulphate solution into a beaker3. Dip the magnesium and copper strips into copper(II) sulphate solution4. Complete the circuit5. Record the potential difference / reading of voltemeter6. Determine the metals strips which become the negative / positive

terminal7. Repeat Step 1 – 6 by replacing pairs of magnesium/copper with

aluminium/copper, iron/copper and lead/copperTabulation of data

Pair of electrodes Potential difference (V) Negative/ positive terminalMg / CuAl / CuFe / CuPb / Cu

In a simple voltaic cell, when two different metals are dipped into an electrolyte, the metal which situated higher in the electrochemical series will donate electrons and become the negative terminal

H

HH

H

C C

H

O

C O H

Essay

(a) Alcohol R contains four carbon atoms and is able to show isomerism.Draw and name the structural formulae of two isomers of alcohol R.

[4 marks](b) Table 7 shows two structural formulae of carbon compounds of P and Q.

Carbon compound Structural formula

P

Q

Based on Table 7, compare carbon compounds P and Q. [6 marks]

Table 7