• 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. Free essay

    Group II metals

    Any observations were recorded. Hydrochloric acid was added drop by drop to each of the three test tubes. After every drop, the test tubes were shaken in order to enable the solution to mix properly. The colour changes were recoded.

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

    The most likely sources of impurities could be the presence of water in the sample as it is very difficult to remove water from a product completely. The best way to determine the amount of acid salicylic acid present was to do titrimetric analysis.

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

    The tube was stoppered and inverted for a few times to ensure thorough mixing of content. 15. A portion of the solution was poured into a sample tube and was put in the colorimeter every 30 seconds and the absorbance was recorded.

  2. 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.

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

    Procedural uncertainties and improvements: There are a number of procedural uncertainties for method one including the fact that the procedure of heating the iron (II) sulphate to drive off the water is only done twice. The problem with this is that because it is not reheated and weighed continuously until

  2. Aim: To determine how the concentration of each species in a reaction affects the ...

    Therefore, collisions become more likely. More collisions take place, leading to a faster rate of reaction. Preliminary Test A preliminary test involved the teacher carrying out the experiment and me watching this. This enabled me to understand exactly how to carry out the experiment and also determine ways in which I would carry out the experiment more accurately.

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