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SENIOR HIGH SCHOOL REPORTChem Lab - Lab Report. Redox equations. Im sure everyone that has done anytype of chemistry at any time in there lives have done this experiment. Anyway if u want the original just msg me where u want it sent.
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Mark Riley 3107631608 Investigating Redox Reactions 1
Investigating Redox Reactions
Mark Riley
Introduction Redox reactions are oxidation-reduction reactions which are complementary chemical reactions characterised by the loss or gain, respectively, of one or more electrons by a substance.
Task Practical Report
Aim To determine the redox reaction that has taken place after mixing some common oxidants and reactants.
Procedure This experiment has been split into 7 parts. A separate procedure for each test is given.
Also- See page 6 of the Practical Activities handbook
Equipment Safety glasses, test tube rack, 7 test tubes, reagents in dropping bottle
Mark Riley 3107631608 Investigating Redox Reactions 2
The ๐ธ0 given for each half and overall equations have been highlighted as they are only hypothetical values
(eg. if one mole of each was used, at 25oc, oxidation and reduction separated etc in a voltaic battery)
1. Reaction of acidified hydrogen peroxide with iron sulphate
5 drops of ๐ป2๐2, 5 drops of ๐ป2๐๐4 and 10 drops of ๐น๐๐๐4 were added to a test tube. 1 drop of
KSCN was added and as a result the solution turned blood red indicating the presence of ๐น๐3+.
๐ป2๐2 has a higher oxidising strength (oxidant) and ๐น๐2+ has a higher reducing strength
(reductant) โด the ๐น๐2+ was oxidized and ๐ป2๐2 was reduced according to the following equation.
๐น๐2+ โ ๐น๐3+ + ๐ ร 2 โ 0.77V
๐ป2๐2 + 2๐ป+ + 2๐ โ 2๐ป2๐ + 1.78V
๐ป2๐2 + 2๐ป+ + 2๐น๐2+ โ 2๐ป2๐ + 2๐น๐3+ โV = 1.01V
2. Reaction of acidified hydrogen peroxide with potassium iodide
5 drops of ๐ป2๐2, 5 drops of ๐ป2๐๐4 and 10 drops of ๐พ๐ผ(white crystalline solid, colourless in
solution) were added to a test tube. 3 drops of starch were added turning the solution blue-black
indicating the presence of iodine ๐ผ2.
๐ป2๐2 has a higher oxidising strength (oxidant) and ๐ผโ has a higher reducing strength (reductant) โด
the ๐ผโ was oxidized and ๐ป2๐2 was reduced according to the following equation.
2๐ผโ โ ๐ผ2 + 2๐ โ 0.54V
๐ป2๐2 + 2๐ป+ + 2๐ โ 2๐ป2๐ + 1.78V
๐ป2๐2 + 2๐ป+ + 2๐ผโ โ 2๐ป2๐ + ๐ผ2 โV = 1.24V
Mark Riley 3107631608 Investigating Redox Reactions 3
3. Reaction of acidified potassium permanganate with iron(II)sulphate
3 drops of ๐พ๐๐๐4, 6 drops of ๐ป2๐๐4 and 20 drops of ๐น๐๐๐4 were added to a test tube. The
solution was initially purple but then turned colourless indicating that the ๐๐๐4โ had been
reduced to ๐๐2+. 1 drop of KSCN was added and as a result the solution turned blood red
indicating the presence of ๐น๐3+.
๐๐๐4โ has a higher oxidising strength (oxidant) and ๐น๐2+ has a higher reducing strength
(reductant) โด the ๐น๐2+ is oxidized and ๐๐๐4โ is reduced according to the following equation.
๐น๐2+ โ ๐น๐3+ + ๐ ร 5 โ 0.77V
๐๐๐4โ + 8๐ป+ + 5๐ โ ๐๐2+ + 4๐ป2๐ + 1.51V
๐๐๐4โ + 8๐ป+ + 5๐น๐2+ โ ๐๐2+ + 4๐ป2๐ + 5๐น๐3+ โV = 0.74
4. Reaction of acidified potassium permanganate with potassium iodide
3 drops of ๐พ๐๐๐4, 6 drops of ๐ป2๐๐4 and 20 drops of ๐พ๐ผ(white crystalline solid, colourless in
solution) were added to a test tube. The solution was initially purple but then turned colourless
indicating that the ๐๐๐4โ had been reduced to ๐๐2+. 3 drops of starch were added turning the
solution blue-black indicating the presence of iodine ๐ผ2. A precipitate was also present.
๐๐๐4โ has a higher oxidising strength (oxidant) and 2๐ผโ has a higher reducing strength (reductant)
โด the 2๐ผโ is oxidized and ๐๐๐4โ is reduced according to the following equation.
2๐ผโ โ ๐ผ2 + 2๐ ร 5 โ 0.54V
๐๐๐4โ + 8๐ป+ + 5๐ โ ๐๐2+ + 4๐ป2๐ ร 2 + 1.51V
2๐๐๐4โ + 2 ร 8๐ป+ + 5 ร 2๐ผโ โ 2๐๐2+ + 2 ร 4๐ป2๐ + 5๐ผ2
2๐๐๐4โ + 16๐ป+ + 10๐ผโ โ 2๐๐2+ + 8๐ป2๐ + 5๐ผ2 โV = 0.97
Mark Riley 3107631608 Investigating Redox Reactions 4
5. Reaction of acidified potassium dichromate with potassium iodide
2 drops of ๐พ2๐ถ๐2๐7, 6 drops of ๐ป2๐๐4 and 15 drops of ๐พ๐ผ (white crystalline solid, colourless in
solution) were added to a test tube. The orange solution turned blue/green indicating that the
๐ถ๐2๐72โ had been reduced to ๐ถ๐3+. 3 drops of starch were added turning the solution blue-black
indicating the presence of iodine ๐ผ2.
๐ถ๐2๐72โ has a higher oxidising strength (oxidant) and 2๐ผโ has a higher reducing strength
(reductant) โด the 2๐ผโ is oxidized and ๐ถ๐2๐72โ is reduced according to the following equation.
2๐ผโ โ ๐ผ2 + 2๐ ร 3 โ 0.54V
๐ถ๐2๐72โ + 14๐ป+ + 6๐ โ 2๐ถ๐3+ + 7๐ป2๐ + 1.23V
๐ถ๐2๐72โ + 14๐ป+ + 6๐ผโ โ 2๐ถ๐3+ + 7๐ป2๐ + 3๐ผ2 โV = 0.69V
6. Reaction of iron(III)chloride with acidified hydrogen peroxide
5 drops of ๐น๐๐ถ๐3 , 5 drops of ๐ป2๐๐4 and 5 drops of ๐ป2๐2 were added to a test tube. 1 drop of
KSCN was added, the colour of the solution was unchanged indicating that no ๐น๐3+ was present.
The solution fizzled indicating a the release of oxygen gas ๐2.
๐น๐3+ has a higher oxidising strength (oxidant) and ๐ป2๐2 has a higher reducing strength
(reductant) โด the ๐ป2๐2 is oxidized and ๐น๐3+ is reduced according to the following equation.
๐น๐3+ + ๐ โ ๐น๐2+ ร 2 + 0.77V
๐ป2๐2 โ ๐2 + 2๐ป+ + 2๐ โ 0.70V
๐ป2๐2 + 2๐น๐3+ โ ๐2 + 2๐ป+ + 2๐น๐2+ โV = 0.07V
Mark Riley 3107631608 Investigating Redox Reactions 5
7. Reaction of acidified potassium permanganate with hydrogen peroxide
3 drops of ๐พ๐๐๐4, 6 drops of H2๐๐4 and 10 drops of ๐ป2๐2 were added to a test tube. The
solution fizzled indicating the release of oxygen gas ๐2.
๐๐๐4โ has a higher oxidising strength (oxidant) and ๐ป2๐2 has a higher reducing strength
(reductant) โด the ๐ป2๐2 is oxidized and ๐๐๐4โis reduced according to the following equation.
๐ป2๐2 โ ๐2 + 2๐ป+ + 2๐ ร 5 โ 0.70V
๐๐๐4โ + 8๐ป+ + 5๐ โ ๐๐2+ + 4๐ป2๐ ร 2 + 1.51V
2๐๐๐4โ + 2 ร 8๐ป+ + 5๐ป2๐2 โ 2๐๐2+ + 2 ร 4๐ป2๐ + 5๐2 + 5 ร 2๐ป+
2๐๐๐4โ + 16๐ป+ + 5๐ป2๐2 โ 2๐๐2+ + 8๐ป2๐ + 5๐2 + 10๐ป+
2๐๐๐4โ + 6๐ป+ + 5๐ป2๐2 โ 2๐๐2+ + 8๐ป2๐ + 5๐2 โV = 0.81
Conclusion
Redox reactions were balanced in the form of chemical equations by arranging the quantities of
the substances involved so that the number of electrons lost by one substance is equaled by the
number gained by another substance. In redox reactions, the substance losing electrons
(undergoing oxidation) is a good electron donor, or reductant because lost electrons are given to
and reduce the other substance. The other substance that gained electrons (undergoing
reduction) is an electron acceptor, or oxidant. Hydrogen peroxide was capable of acting as a
reductant as well as an oxidant.