Effect of different metal pairs on the emf for a Voltaic cell

Procedure/Method • Cut metal strips into (1cmx1cm) for Zn, Mg, Al, Fe, Sn and Cu

• Polish them with sandpaper

• Prepare 1.0M Zn(NO3)2, Mg(NO3)2, AI(NO3)3, Fe(NO3)3, Sn(NO3)2 and Cu(NO3)2

• Pipette 5ml of Cu(NO3)2 into (+) side of well

• Insert Cu metal into Cu(NO3)2 solution and connect to (+) side of voltmeter

• Prepare Salt bridge by soaking a cotton string in saturated NaCI solution

• Pipette 5ml of Zn(NO3)2 into (-) side of well

• Place salt bridge shown above

• Measure the emf of Zn/Cu voltaic cell

•Repeat the steps with different metals pairs shown below

• Compare your results with theoretical values calculated using Nersnt Equation

• Experiment repeated to measure the current produced using different metal pairs

Results

Potential Difference/V

Current produced/A

Research Questions: • Effect of Different metal pairs on the emf in Voltaic Cell • Effect of Different metal pairs on the current produced in Voltaic Cell

Effect of different metal pairs on the emf for a Voltaic cell

Effect of ZnSO4 Concentration on emf for Zn/Cu Voltaic cell

Procedure/Method • Cut Cu/Zn into (1cm x1cm) and polish them with sandpaper

• Prepare 1.0M CuSO4

• Pipette 5ml of CuSO4 into (+) side of well

• Insert Cu metal into CuSO4 solution and connect to (+) side of voltmeter

• Prepare salt bridge by soaking a cotton string in saturated NaCI solution

• Pipette 5ml of 1.0M ZnSO4 into (-) side of well

• Place salt bridge shown above

• Measure the emf of Zn/Cu voltaic cell

•Repeat the steps with different ZnSO4 concentration shown below

• Compare your results with theoretical values calculated using Nernst Equation

• Experiment repeated to measure the current using different ZnSO4 concentration

Results

Potential Difference/V

Current produced/A

Research Questions: • Effect of ZnSO4 concentration on the emf in Zn/Cu Voltaic Cell • Effect of ZnSO4 concentration on the current produced in Zn/Cu Voltaic Cell

Effect of ZnSO4 Concentration on emf for Zn/Cu Voltaic cell

Effect of CuSO4 Concentration on emf for Zn/Cu Voltaic cell

Procedure/Method • Cut Cu/Zn into (1cmx1cm) and polish them with sandpaper

• Prepare 1.0M CuSO4

• Pipette 5ml of CuSO4 into (+) side of well

• Insert Cu metal into CuSO4 solution and connect to (+) side of voltmeter

• Prepare salt bridge by soaking a cotton string in saturated NaCI solution

• Pipette 5ml of 1.0M ZnSO4 into (-) side of well

• Place salt bridge shown above

• Measure the emf of Zn/Cu voltaic cell

•Repeat the steps with different CuSO4 concentration shown below

• Compare your results with theoretical values calculated using Nernst Equation

• Experiment repeated to measure the current using different CuSO4 concentration

Results

Potential Difference/V

Current produced/A

Research Questions: • Effect of CuSO4 concentration on the emf in Zn/Cu Voltaic Cell • Effect of CuSO4 concentration on the current produced in Zn/Cu Voltaic Cell

Effect of CuSO4 Concentration on emf for Zn/Cu Voltaic cell

Effect of ZnSO4 and CuSO4 Concentration on emf in Zn/Cu Voltaic cell

Procedure/Method • Cut Cu/Zn into (1cm x1cm) and polish them with sandpaper

• Prepare 1.0M CuSO4

• Pipette 5ml of CuSO4 into (+) side of well

• Insert Cu metal into CuSO4 solution and connect to (+) side of voltmeter

• Prepare salt bridge by soaking a cotton string in saturated NaCI solution

• Pipette 5ml of 1.0M ZnSO4 into (-) side of well

• Place salt bridge shown above

• Measure the emf of Zn/Cu voltaic cell

•Repeat the steps with different ZnSO4 and CuSO4 concentration shown below

• Compare your results with theoretical values calculated using Nernst Equation

• Experiment repeated to measure current using different ZnSO4 and CuSO4 conc

Results

Potential Difference/V

Current produced/A

Research Questions: • Effect of ZnSO4 and CuSO4 conc on the emf in Zn/Cu Voltaic Cell • Effect of ZnSO4 and CuSO4 conc on the current produced in Zn/Cu Voltaic Cell

Effect of ZnSO4 and CuSO4 Concentration on emf in Zn/Cu Voltaic cell

Effect of Temperature on emf in Zn/Cu Voltaic cell

Procedure/Method • Cut Cu/Zn into (1cmx1cm) and polish them with sandpaper

• Prepare 1.0M CuSO4 and ZnSO4 at room temperature (25C)

• Pipette 5ml of CuSO4 into (+) side of well

• Insert Cu metal into CuSO4 solution and connect to (+) side of voltmeter

• Prepare salt bridge by soaking a cotton string in saturated NaCI solution

• Pipette 5ml of 1.0M ZnSO4 into (-) side of well

• Place salt bridge shown above

• Measure the emf of Zn/Cu voltaic cell

•Repeat the steps with CuSO4 and ZnSO4 at different temperature shown below

• Compare your results with theoretical values calculated using Nernst Equation

• Experiment repeated to measure the current at different temperature shown below

Potential Difference/V

Current produced/A

Research Questions: • Effect of Temperature on the emf in Zn/Cu Voltaic Cell • Effect of Temperature on the current produced in Zn/Cu Voltaic Cell

Effect of Temperature on emf in Zn/Cu Voltaic cell

Effect of electrode size of Zn and Cu on emf for Zn/Cu Voltaic cell

Procedure/Method • Cut Cu/Zn into (1cmx1cm) and polish them with sandpaper

• Prepare 1.0M CuSO4

• Pipette 5ml of CuSO4 into (+) side of well

• Insert Cu metal into CuSO4 solution and connect to (+) side of voltmeter

• Prepare salt bridge by soaking a cotton string in saturated NaCI solution

• Pipette 5ml of 1.0M ZnSO4 into (-) side of well

• Place salt bridge shown above

• Measure the emf of Zn/Cu voltaic cell

•Repeat the steps with different electrode size shown below

• Compare your results with theoretical values calculated using Nernst Equation

• Experiment repeated to measure the current with different electrode size shown below

Potential Difference/V

Current produced/A

Research Questions: • Effect of Electrode Size on the emf in Zn/Cu Voltaic Cell • Effect of Electrode Size on the current produced in Zn/Cu Voltaic Cell

Effect of electrode size of Zn and Cu on emf for Zn/Cu Voltaic cell

Effect of different anion on emf for Zn/Cu Voltaic cell

Procedure/Method • Cut Cu/Zn into (1cm x1cm) and polish them with sandpaper

• Prepare 1.0M CuSO4

• Pipette 5ml of CuSO4 into (+) side of well

• Insert Cu metal into CuSO4 solution and connect to (+) side of voltmeter

• Prepare salt bridge by soaking a cotton string in saturated NaCI solution

• Pipette 5ml of 1.0M ZnSO4 into (-) side of well

• Place salt bridge shown above

• Measure the emf of Zn/Cu voltaic cell

•Repeat the steps with different salt solution (different anions) shown below

• Compare your results with theoretical values calculated using Nernst Equation

• Experiment repeated to measure the current with salt solutions shown below

Potential Difference/V

Current produced/A

Research Questions: • Effect of different anions on the emf in Zn/Cu Voltaic Cell • Effect of different anions on the current produced in Zn/Cu Voltaic Cell

Effect of different anion on emf for Zn/Cu Voltaic cell

Effect of salt bridge concentration on emf for Zn/Cu Voltaic cell

Procedure/Method • Cut Cu/Zn into (1cm x1cm) and polish them with sandpaper

• Prepare 1.0M CuSO4

• Pipette 5ml of CuSO4 into (+) side of well

• Insert Cu metal into CuSO4 solution and connect to (+) side of voltmeter

• Prepare salt bridge by soaking a cotton string in 0.5% NaCI concentration

• Pipette 5ml of 1.0M ZnSO4 into (-) side of well

• Place salt bridge shown above

• Measure the emf of Zn/Cu voltaic cell

•Repeat the steps with different salt bridge concentration shown below

• Compare your results with theoretical values calculated using Nernst Equation

• Experiment repeated to measure the current with different salt bridge concentration

Potential Difference/V

Current produced/A

Research Questions: • Effect of Salt Bridge Concentration on the emf in Zn/Cu Voltaic Cell • Effect of Salt Bridge Concentration on the current produced in Zn/Cu Voltaic Cell

Effect of salt bridge concentration on emf for Zn/Cu Voltaic cell

Effect of CuSO4 concentration on emf for Copper Concentration cell

Procedure/Method • Cut Cu into (1cm x1cm) and polish them with sandpaper

• Prepare 1.0M CuSO4 and pipette 5ml of CuSO4 into (+) side of well

• Insert Cu metal into CuSO4 solution and connect to (+) side of voltmeter

• Prepare salt bridge by soaking a cotton string in saturated NaCI solution

• Prepare 2 fold serial dilution of 1.0M CuSO4 (0.5, 0.25, 0.125, 0.0625M)

• Pipette 5ml of 0.5M CuSO4 into (-) side of well

• Insert Cu metal strip into and connect to (-) terminal of voltmeter

• Place salt bridge shown above

• Measure the emf of Cu 2+(1.0M)/Cu 2+(0.5M) concentration cell

•Repeat the steps with different CuSO4 concentration shown below

• Compare your results with theoretical values calculated using Nernst Equation

• Experiment repeated to measure the current with different CuSO4 concentration

Potential Difference/V

Current produced/A

Research Questions: • Effect of CuSO4 Concentration on the emf in Copper Concentration Cell • Effect of CuSO4 Concentration on the current produced in Copper Concentration Cell

Effect of CuSO4 concentration on emf for Copper Concentration cell

How different metals are used to displace another metal from its salt solution?

Procedure/Method • Cut Mg, Zn, Fe, Sn and Cu into (1cm x1cm) and polish them with sandpaper

• Prepare 0.1M Mg(NO3)2, Zn(NO3)2, Fe(NO3)3, Sn(NO3)2, Pb(NO3)2 and Cu(NO3)2

• Pipette 5ml of 0.1M of different nitrate solutions into 6 different wells shown below

• Place a strip of Mg into 6 different wells

• Record down all observation on colour change, metal deposit or any metal strip dissolves

• Place a √ if any displacement reaction has taken place or X if no visible observations

•Repeat the steps with different metal strips and record down observation shown below shown below

Metal strips

Nitrate salt solutions

How different metals are used to displace another metal from its salt solution?

Metal strips

Nitrate salt solutions

Results

• Metal higher in reactivity series, displace lower metal from its solution

• Mg is more reactive than Cu, able to displace Cu from its solution

• Mg → Mg 2+ + 2e (lose e, Oxidation )

• Cu 2+ + 2e → Cu (gain e, Reduction )

Observation

• Mg metal dissolves

• Brown deposit, Cu forms

• Blue solution CuSO4 turn pale /colourless

Conclusion

Mg > Zn > Fe > Sn >Pb > Cu

Effect of different metals on the rusting of iron

Procedure/Method • Clean 5 pieces of iron nail with sandpaper

• Wrap each nail with different metals, Mg, Zn, Sn, Cu shown in diagram above

• Place each nail into test tube with 10ml of water

• Add 2 drops of phenolphthalein indicator and 2 drops of potassium hexacyanoferrate (III)

• Leave iron nail for 2 days and record down all observations in table below

Notes :

• Potassium hexacyanoferrate(III) reacts with Fe 2+ producing dark blue colouration

• Phenolphthalein – to detect OH- ions, if solution is alkaline it will turn pink

Effect of different metals on the rusting of iron

Results (Mg + Fe) and (Zn + Fe) – No rusting and solution turns pink

(Cu + Fe) and (Sn + Fe) – Rusting and solution turns blue

Acknowledgements

Thanks to source of pictures and video used in this presentation Thanks to Creative Commons for excellent contribution on licenses http://creativecommons.org/licenses/

Prepared by Lawrence Kok

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