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Redox reaction Group C


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  • I like the abundant of colours available! Good Job 8.7/10

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  • 3 things I like:
    - original format of presentation! More continuous format so that's quite refreshing :)
    - thanks for taking time to choose good images
    - all the definitions of oxidation and reduction were well explored

    2 things that can be worked on:
    - consider changing the contrast of the pictures so that your words stand out more
    - may also consider having less words per slide and let your examples do more of the 'talking'

    1 question:
    - Try my quizzzzzzz

    Slide 4: Be consistent in the use of state symbols. O2 (g) should be added in :)
    Slide 6: You may want to illustrate this point better by using a half-equation
    Slide 9: Specify which oxidation state of copper in copper oxide. Eg. Copper(II) oxide or copper(I) oxide. Just copper oxide is generally not accepted at O-levels
    Slide 11: Give a complete equation here. There is no such thing as iron(III). It's always iron(III) something... eg. iron(III) chloride, iron(III) sulfate, etc
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  • NIce pictures, informative texts, entertaining pictures. The font and pictures don't go well with each other. The texts are at time too long. Where did you get the pictures? no errors. -Syakiran Group B
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  • 3 things i like: its informative. Pictures used are good. Length of slide is quite fine.

    2 things that can be improved : The picture and words do not contrast each other making it difficult to read. Maybe you can also minimise the words so that it does not look so wordy.

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  • The pictures and the font together very hard to see
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Redox reaction Group C

  1. 1. RedoxReaction
  2. 2. Oxidation is a reactionwhere oxygencombines with anelement/compound toform anothersubstance
  3. 3. Oxidation – Gain of oxygenWhen calcium burns in oxygen, the followingreaction takes placecalcium + oxygen  calcium oxide2Ca(s) + O2  2CaO(s)Since calcium has gained oxygen. It has beoxidised. Hence this is oxidation.
  4. 4. Oxidation – Loss of HydrogenWhen ammonia is passed over heated copper(II)oxide, the following reaction takes place.ammonia + copper(II) oxide  nitrogen +copper + water vapour2NH3(g) + 3CuO(s)  N2(g) + 3Cu(s) + 3H2O(g)Since ammonia has lost hydrogen, it has beenoxidised.
  5. 5. Oxidation – Loss of ElectronsOxidation can still take place despite having nooxygen/hydrogen. When a substance loseselectrons it is considered oxidation.magnesium + chlorine  magnesium chlorideMg(s) + Cl2(g)  MgCl2(s)
  6. 6. What is Reduction?
  7. 7. Definition Of Reduction• Reduction is a chemical reaction where it loses oxygen, gain hydrogen, gain electron and have a decrease in oxidation state by a molecule, atom or ion.• A reactant that reduces another substance is a reducing agent.• The reducing agent transfers electrons to another substance, it reduces others, and is thus itself oxidized. And, because it "donates" electrons, it is also called an electron donor.
  8. 8. Reduction-Loss Of OxygenWhen zinc burns in copper(II) oxide, thefollowing reaction takes place.Zinc + copper oxide  Zinc oxide + copperZn(s)+CuO(s)  ZnO(s)+Cu(s)Since Zinc has gain oxygen,it is oxidised.Copper(II) oxide loses oxygen,thus it is reduced.
  9. 9. Reduction-Gain Of HydrogenWhen nitrogen burns with hydrogen gas, thefollowing reaction takes place.Nitrogen +Hydrogen  AmmoniaN2 + 3H2  2NH3Nitrogen gain hydrogen, thus it is being reduced.
  10. 10. Reduction-Gain Of Electron When iron reacts with chloride acid, thefollowing reaction takes place.Iron + chlorine  Iron(III) + Chloride2Fe2++Cl2  2Fe3++2Cl-Since iron loses electron, it is oxidised. Chlorinegains electron, thus it is reduced.
  11. 11. Common Reducing Agent• Lithium aluminium hydride (LiAlH4)• Nascent (atomic) hydrogen• Sodium amalgam• Diborane• Sodium borohydride (NaBH4)• Compounds containing the Sn2+ ion, such as tin(II) chloride• Sulfite compounds• Hydrazine (Wolff-Kishner reduction)• Zinc-mercury amalgam (Zn(Hg)) (Clemmensen reduction)• Diisobutylaluminum hydride (DIBAL-H)• Lindlar catalyst• Oxalic acid (C2H2O4)• Formic acid (HCOOH)• Ascorbic acid (C6H8O6)• Phosphites, hypophosphites, and phosphorous acid• Dithiothreitol (DTT) – used in biochemistry labs to avoid S-S bonds• Compounds containing the Fe2+ ion, such as iron(II) sulfate• Carbon monoxide(CO)• Carbon (C)
  12. 12. Oxidation State
  13. 13. The oxidation state is thecharge an atom of anelement would have if itexisted as an ion in acompound.
  14. 14. To work out the oxidation state of an atom, we apply the following rules:Rule Example Oxidation state1. The oxidation state of a Cu, S, Cl2 0, 0, 0free element is zero.2. The oxidation state of a K+, Zn2+, Cl-, O2- +1, +2, -1, -2simple ion is the same asthe charge on the ion.3. The oxidation states of Ca, C, 3O +2, +4, 3x(-2)=-6the atoms present in theformula of a compound All add up to zero.add up to zero. Theexample shown here isCaCO3 .4. The total of the S, 4O +6, 4x(-2)=-6oxidation states of theatoms in a polyatomic ion All add up to equal to the charge onthe ion. The exampleshown here is SO4 2- .
  15. 15. Solution to question: Find the oxidation state of each element in ammonium sulfate.(NH4)2SO4Since hydrogen in NH4 has an o.s of +1,Ammonium has a charge of 1.Let n be x2(x+4(1))=22x-2-8x=-3Hence nitrogen has an o.s of -3
  16. 16. Since oxygen in SO4 has an o.s of -2,Sulfate has a charge of -2.Let s be yy+4(-2)=-2y-8=-2y=6Hence sulfur has an o.s of 6.
  17. 17. SourceCHEMISTRY Matters textbookGoogle
  18. 18. Done by• Edwin• Kian Leong• Jeremy• Melvan