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Oxidation Reduction
AQA A Level Chemistry
| Question | Answer |
|---|---|
| What is oxidation in terms of oxygen? | The gain of oxygen |
| What is oxidation in terms of electrons? | The loss of electrons |
| What does an oxidising agent do? | Donate oxygen/accept electrons (it is reduced) |
| What is reduction in terms of oxygen? | The loss of oxygen |
| What is reduction in terms of electrons? | The gain of electrons |
| What does a reducing agent do? | Accept oxygen/donate electrons (it is oxidised) |
| What are redox reactions? | Reactions in which both oxidation and reduction occur |
| What is the oxidation state for an element ie Fe/Cl2 | Zero |
| What is the oxidation state of a metal in its compound? | The charge on the ion that it forms |
| What is the oxidation state of an oxygen atom in a compound? | it is -2 unless it is in a peroxide (H2O2) when it is -1 |
| What is the oxidation state of an hydrogen atom in a compound? | it is +1 unless in a hydride (NaI) when it is -1 |
| What is the oxidation state of Cl in a compound? | it is -1 unless when bonded to F/O when it can have positive values |
| What is disproportionation? | A redox reaction in which the oxidation state of some atoms of a particular element increase in oxidation state and of others decrease in oxidation state |
| What is the oxidation state of chromium in the Cr²⁺ ion? | "+2" |
| What is the oxidation state of chromium in the CrCl₃? | "+3" |
| What is the oxidation number of iron in iron (III) oxide? | "+3" |
| What is the oxiddation state of K in K2MnO4? | "+1" |
| What is the oxiddation state of O in K2MnO4? | "-2" |
| What is the oxiddation state of Mn in K2MnO4? | "+6" |
| Write a half equation to show a sodium atom forming a sodium ion | Na → Na+ + e- |
| "Write a half equation for the following change: Cr2O72- → Cr3+ | " Cr2O7 2-+ 14H+ + 6 e- → 2 Cr3+ + 7 H+ |
| Write half equation for MnO4- → Mn2+ and Cl- →Cl2 then combine them | 2x(MnO4- +5e- + 8H+ → Mn2+ + 4H2O) + 5x(2Cl- →Cl2 +2e-) = 2MnO4- + 16H+ + 10Cl- → 2Mn2+ + 8H2O + 5Cl2 |