Redox Reactions C
Aperçu
A blast furnace in Nigeria, Brazil or China spends its whole working life pulling oxygen off iron ore, and the moment the finished steel leaves the mill the air begins putting that oxygen back. Extraction and rusting look like completely unrelated pieces of chemistry. They are the same process running in opposite directions, and once you can see that, an enormous amount of this course stops being a list of separate reactions and turns into one idea wearing different clothes.
That idea is redox. This lesson gives you two ways of recognising it: an older definition built on oxygen, which is easy to use and works on maybe a third of the reactions you meet, and a deeper one built on electrons, which works on all of them. You will finish able to look at any equation on the specification, from a burning fuel to a lump of scrap iron in a copper solution, and say without hesitation which substance was oxidised, which was reduced, and how you know.
Objectifs
- Oxidation can be described as the gain of oxygen by a substance and reduction as the loss of oxygen from a substance.
- Oxidation can also be described as the loss of electrons and reduction as gain of electrons. Students should be able to describe chemical reactions within this specification in terms of oxidation and reduction using the definitions above.
- When oxidation and reduction are happening at the same time this is known as a redox reaction, for example: Reduction Fe2O3 + 3 CO 2 Fe + 3 CO2 Oxidation
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Félicitations, vous avez terminé la leçon sur Redox Reactions C. Maintenant que vous avez exploré le concepts et idées clés, il est temps de mettre vos connaissances à lépreuve. Cette section propose une variété de pratiques des questions conçues pour renforcer votre compréhension et vous aider à évaluer votre compréhension de la matière.
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Utilisez cette section d'évaluation comme une occasion de renforcer votre compréhension du sujet et d'identifier les domaines où vous pourriez avoir besoin d'étudier davantage. Ne soyez pas découragé par les défis que vous rencontrez ; considérez-les plutôt comme des opportunités de croissance et d'amélioration.
- Which of these describes oxidation? A. gain of electrons B. loss of electrons C. loss of oxygen D. gain of protons Answer: B
- In the reaction Fe2O3 + 3 CO -> 2 Fe + 3 CO2, which substance is oxidised? A. Fe2O3 B. CO C. Fe D. CO2 Answer: B
- A half equation is written as Cu2+ + 2 e- -> Cu. What does this half equation show? A. Copper ions are oxidised because they gain electrons. B. Copper ions are reduced because they gain electrons. C. Copper atoms are oxidised because they lose electrons. D. Copper atoms are reduced because they lose oxygen. Answer: B
- Zinc is added to copper(II) sulfate solution: Zn + CuSO4 -> ZnSO4 + Cu. Which statement is correct? A. Zinc is reduced and copper ions are oxidised. B. Zinc is oxidised and copper ions are reduced. C. Both zinc and copper ions are oxidised. D. Neither zinc nor copper ions change, because no oxygen is present. Answer: B
- Which statement about a redox reaction is correct? A. Oxidation happens first and reduction happens afterwards. B. Only reactions containing oxygen can be redox reactions. C. Oxidation and reduction take place at the same time. D. The number of electrons lost is always greater than the number gained. Answer: C
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"Chemistry: Balancing Oxidation-Reduction Reactions" by OpenStax, OpenStax, Rice University, licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Source: https://openstax.org/books/chemistry/pages/17-1-balancing-oxidation-reduction-reactions. Access for free at https://openstax.org/books/chemistry/pages/1-introduction
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Classifying Chemical Reactions
Define three common types of chemical reactions (precipitation, acid-base, and oxidation-reduction)
"Chemistry: Classifying Chemical Reactions" by OpenStax, OpenStax, Rice University, licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Source: https://openstax.org/books/chemistry/pages/4-2-classifying-chemical-reactions. Access for free at https://openstax.org/books/chemistry/pages/1-introduction
Publiées par d'autres organisations sous licence libre, créditées comme elles le demandent. Les liens ouvrent leurs sites.
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