• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Electrochemistry - Redox reaction.

Extracts from this document...

Introduction

INTRODUCTION One reactant is oxidized and another reactant is reduced, this chemical reaction is called Redox reaction. Redox reactions involve in generation of electricity in electrochemical cells. [1] Two different solid metals in solution of their ions made up of electrochemical cell, which are connected by a salt bridge or a wire. Each metal is an electrode, which will either be oxidized or reduced in a half-cell. [2] The pairs of species, e.g. Zn2+(a.q)/Zn(s) and Cu2+(a.q)/Cu(s), etc. are known as redox couple. The relative oxidizing or reducing strengths of redox couples are expressed in terms of their standard electrode potentials, EO, which have the units of Volts.[3] A general cell diagram for an electrochemical cell is shown below: fig 1 [2] The standard potential of the cell, EO=EOR-EOL where EOR =the EO of the right-hand-side electrode and EOL= the EO of the left-hand-side electrode.[4] Aim of the experiment was to understand how electricity worked to form a simple circuit. This experiment had three sub-experiments. First was to build a simple circuit. Second was to make an electrochemical cell. ...read more.

Middle

Fe2+(a.q) + 2e- Reduction: Ni2+(a.q) + 2e- Ni (s) Reduction: Ni2+(a.q) + 2e- Ni(s) Redox reaction: Redox reaction: Zn(s)+ Ni2+(a.q) Zn2+(a.q)+ Ni (s) Ni(s)+ Fe2+(a.q) Ni2+(a.q)+ Fe (s) 5 FeSO4 & CuSO4 V = 0.6V Oxidation: Fe(s) Fe2+(a.q) + 2e- Reduction: Cu2+(a.q) + 2e- Cu (s) Redox reaction: Fe (s)+ Cu2+(a.q) Fe2+(a.q)+ Cu (s) EXPERIMENT III. Zn & Cu: Fe & Zn: V = 0.839 V V = 0.337 V Ni & Zn: Ni & Fe: V = 0.757 V V = 0.513 V DISCUSS EXPERIMENT II A negative EO means that a redox couple is a stronger reducing agent than the H+(a.q)/H2(g) couple. A positive EO means that a redox couple is a weaker reducing agent than the H+(a.q)/H2(g) couple. [5] 1 ZnSO4 & CuSO4 The Table of Standard Electrode Potentials, which was attached as Appendix A, suggested that Zn is better reducing agent than Cu and Cu2+ ions were better oxygenating agent than Zn2+. Oxidation = Lose e- According to fig.1 (page 1, introduction), Zn side was the anode of the cell and Cu side was the cathode of the cell. ...read more.

Conclusion

EXPERIMENT III The lemon battery experiment was the same rule as the experiment II. Only half lemon was used in this experiment. Electrodes Zn and Cu were placed into the lemon. Zn was oxidized and ions were coming off. Chemical equation was Zn(s) Zn2+(a.q) + 2e-. The Zn2+ ions were flow into the lemon and Zn became negatively charged due to electron loss. Cu was reduced by gaining those electrons from Zn via lemon, hence became positively charged. Chemical equation was Cu2+(a.q) + 2e- Cu(s) Then the ions from negatively charged Zn to positively charged Cu generated electricity and Voltmeter could detect voltage. Voltmeter could detect voltages among electrodes Fe and Zn, Ni and Zn, and Ni and Fe, but the voltages were different due to the different abilities of reduction and oxidation. Reference [1] Lewis R and Evans W(2006) Chemistry. Page100. 3rd Edition. Palgrave Macmillan. New York [2] Handout from Electrochemistry practical sheet. 29th Apr 2008 [3] Lewis R and Evans W(2006) Chemistry. Page107. 3rd Edition. Palgrave Macmillan. New York [4] Lewis R and Evans W(2006) Chemistry. Page109. 3rd Edition. Palgrave Macmillan. New York [5] Lewis R and Evans W(2006) Chemistry. Page110. 3rd Edition. Palgrave Macmillan. New York ?? ?? ?? ?? 1 ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Organic Chemistry section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Organic Chemistry essays

  1. The aim of this experiment is to produce Aspirin. This is an estrification in ...

    Burette (class B) All burettes read to 2 decimal places in which the second figure is either 0 or 5. One drop from a burette has a volume approximately 0.05 cm3. Therefore the precision error is 0.05. Pipette (class B)

  2. Free essay

    Group II metals

    indicator solution Hydrochloric acid A spatula was used to transfer a very small quantity of the three oxides into separate test tubes. The test tubes were shaken after one-third of water was added in it. Observations were recorded. A few drops of universal indicator solution were added into the three test tubes.

  1. Comprehensive and Detailed Chemistry notes

    21% O2, 0.9% Ar and small amounts of other gases such as CO2 Variable. Weather is determined I this layer Stratosphere 15-50 km Ozone (O3) and other gases -50 to 30 at top Mesosphere 50-85 km Ions and atomic particles Approximately -90 Thermosphere 85-600 km Ions and atomic particles Can

  2. The aim of this experiment is to obtain the rate equation for the reaction ...

    9. (Obtaining values for the concentration of iodine) 6 experiments were done for the whole class and our group was responsible for doing experiments a, f and g (varying volume of HCl added) 10. HCl was added to a burette and propanone was added to another burette. 11.

  1. producing electricity through wind power.

    At the moment wind turbines being manufactured now have power ratings ranging from 250 watts - 5 megawatts (MW). A 10-kW wind turbine can generate about 10,000 kWh annually at a site with wind speeds averaging 12 miles per hour, or about enough to power a typical household.

  2. Determination of the formula of Hydrated Iron (II) Sulphate crystals

    Repeat, crucible and Anhydrous Iron (II) sulphate= (0.005/12.80) x 100 =0.04% Total percentage error = 0.04 + 0.03 + 0.04 + 0.04 = 0.15% The total measurement percentage uncertainty is extremely small so any significant discrepancies in the ratio of iron(II) sulphate to water will not be due to measurement errors.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work