7316049
Description
Flashcards by Phoebe Johnson, updated more than 1 year ago
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Created by Phoebe Johnson
over 7 years ago
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| Question | Answer |
| Oxidation | Addition of oxygen Loss of electrons Increase in oxidation number |
| Reduction | Removal of oxygen Gain of electrons Decrease in oxidation number |
| OIL RIG | Oxidation is loss (of electrons) Reduction is gain (of electrons) |
| Oxidising Agent | A species (atom, molecule or ion) that oxidises another species by removing one or more electrons. When an oxidising agent reacts is gains electrons and is, therefore, reduced. |
| Reducing Agent | A species that reduces another species by adding one or more electrons. When a reducing agent reacts it loses electrons and is, therefore, oxidised. |
| Redox Reaction | A reaction that involves both reduction and oxidation |
| In the following equation is Oxygen reduced or oxidised? 2Mg + O2 -> 2MgO | Reduced - it has gained electrons according to the half equation: O2 + 4e- -> 2O2- |
| Disproportionation | A redox reaction where atoms of the same element are simultaneously oxidised and reduced. |
| Oxidation Number | The charge that an ion has or the charge that it would have if the species were fully ionic, represented by a symbol (+ or -) followed by a number unless 0 |
| State three rules for determining oxidation number. | Any of the following: The oxidation number of an uncombined element is 0; the sum of the oxidation numbers of all the elements in a neutral compound is zero or in an ion is equal to the charge of the ion; the more electronegative element in an substance is given a negative oxidation number; the oxidation number of fluorine is always -1; the oxidation number of hydrogen is +1, except when combined with a less electronegative element when it becomes -1; the oxidation number of oxygen is -2, except in peroxides where it is -1 and when combined with fluorine when it is positive |
| What are the oxidation numbers of the elements in the following ion: (SO3)2- | Sulphur: +4 Oxygen: -2 |
| What are the oxidation numbers of the elements in the following ion: [CuCl4]2- | Copper: +2 Chlorine: -1 |
| What are the oxidation numbers of the elements in the following ion: H2O2 | Hydrogen: +1 Oxygen: -1 |
| State the change in oxidation number to zinc in the following ionic half-equation and state whether zinc has been oxidised or reduced: Zn(s) -> Zn2+(aq) + 2e- | 0 to +2 Oxidised - there is an increase in oxidation number |
| State the change in oxidation number to manganese in the following ionic half-equation and state whether manganese has been oxidised or reduced: MnO4- + 8H+ + 5e- -> Mn2+ + 4H2O | +7 to +2 Reduced - there is a decrease in oxidation number |
| Is the following reaction an example of a disproportionation reaction? Mg + 2HCl -> MgCl2 + H2 | No |
| Is the following reaction an example of a disproportionation reaction? 2H2O2 -> 2H2O + O2 | Yes In H2O2 the ox. number of O is -1. This is oxidised to 0 in O2 but reduced to -2 in H2O, hence the reaction is disproportionation. |
| What is a systematic name? | A systematic name of a compound is the name of the compound which specifies the oxidation number of an element using roman numerals in brackets. This is often used for transition metals as opposed to other species as transition metals exist in more than one oxidation state. |
| What is the oxidation state of copper in copper (II) oxide? | +2 |
| What is the oxidation number of lead in lead (IV) oxide? | +4 |
| Combine the following ionic half-equations: 1. MnO4- + 8H+ + 5e- -> Mn2+ + 4H2O 2. H2O2 -> 2H+ + O2 + 2e- | 2MnO4- + 6H+ + 5H2O2 -> 2Mn2+ + 8H2O + 5O2 |
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