"Redox Reaction" PPT

Description

"Redox Reaction" PPT

Part One: Goals and Competencies:

1. Understand and judge redox reactions from the perspective of valence changes and electron transfer. (Macroscopic identification and microscopic analysis)

2. Understand the relationship between redox reactions and the four basic reaction types, and be able to identify redox reactions in combination reactions and decomposition reactions. (Macroscopic identification)

Redox reaction PPT, part 2: independent preview to explore new knowledge

1. Understand redox reactions

1. Understand redox reactions from the perspective of oxygen gain and loss

Analyze the following reactions in terms of oxygen gain and loss and complete the table below.

2CuO+C=====High temperature 2Cu+CO2↑; Fe2O3+3CO=====High temperature 2Fe+3CO2

Conclusion: When a substance gains oxygen and occurs ______, there must be a substance that loses oxygen and occurs ______. The oxidation reaction and the reduction reaction occur simultaneously in one reaction, which is called a redox reaction.

2. Understand redox reactions from the perspective of the increase and decrease of element valence

(1) For the reaction involving oxygen elements 2CuO+C======High temperature　2Cu+CO2↑.

①The valence of copper element is ____, and ____ reaction occurs.

②The valence of carbon element is ____, and ____ reaction occurs.

(2) For reactions involving oxygen-free elements Fe+CuSO4===FeSO4+Cu.

①The valence of copper element is ____, and ____ reaction occurs.

②The valence of iron element is ____, and ____ reaction occurs.

(3) Conclusion: Any reaction involving the element ____ is a redox reaction.

3． Understanding redox reactions from the perspective of electron transfer

(1) In the reaction process of 2Na＋Cl2======△　2NaCl:

①The sodium atom ____ the outermost electron and becomes Na+ with a stable structure. Its valence increases from 0 to ____. A ____ reaction occurs and is ____.

②The outermost layer of the chlorine atom has ____1 electron and becomes Cl- with a stable structure. Its valence is reduced from valence to ____ valence. A ____ reaction occurs and is ____.

③In this reaction, electron exchange occurs between chlorine atoms and sodium atoms, forming anions and cations respectively, which changes the valence of the elements.

Redox Reaction PPT, Part Three: Core Breakthroughs and Overcoming Difficulties

The connection between the concepts of redox reactions

1. The connection between the concepts of redox reactions

2. 4 "not necessarily" in redox reactions

(1) When one element is oxidized, another element may not be reduced. For example, in Cl02+H2O===HCl-1+HClO+1, the oxidized and reduced elements are both chlorine elements.

(2) A reactant does not necessarily exhibit only one property. For example, in the reaction 2KMnO4=====△K2MnO4+MnO2+O2↑, the KMnO4 participating in the reaction shows both reducing and oxidizing properties.

(3) Reactions involving the participation or generation of elemental substances are not necessarily redox reactions. For example, the mutual transformation between isomorphs is not a redox reaction.

(4) When a certain substance changes from a chemical state to a free state, it is not necessarily reduced. For example, HCl→Cl2 is oxidized.

1. Which of the following statements about redox reactions is incorrect ()

A． The substance that loses electrons in the reaction is oxidized, and the substance that gains electrons is reduced.

B. In a redox reaction, the oxidation product and the reduction product can be the same substance.

C． A redox reaction is a reaction in which one substance is oxidized first and then another substance is reduced.

D． There is no reaction with only oxidation and no reduction.

C. The oxidation reaction and the reduction reaction occur at the same time. They are both opposite and unified. The substance being oxidized and reduced in the reaction may be the same substance. ]

2. ClO2 is a water treatment agent with high disinfection and sterilization efficiency and low secondary pollution. ClO2 can be produced in the laboratory through the following reaction: 2KClO3+H2C2O4+H2SO4===2ClO2↑+K2SO4+2CO2↑+2H2O. Which of the following statements is correct ()

A. KClO3 loses electrons during the reaction

B. ClO2 is an oxidation product

C. H2C2O4 is oxidized during the reaction

D. H2SO4 gains electrons and is reduced during the reaction

C. The valence of the Cl element in KClO3 is reduced from +5 to +4, so potassium chlorate gains electrons and a reduction reaction occurs, so A is wrong; the valence of the Cl element is reduced from +5 to +4, so the corresponding product of potassium chlorate is ClO2 It is a reduction product, so B is wrong; the valence of the C element in H2C2O4 increases from +3 to +4 and is oxidized during the reaction, so C is correct; the valence of the elements contained in H2SO4 remains unchanged during the reaction, neither gaining electrons nor Lose electrons. ]

How to represent electron transfer in redox reactions

1. Double line bridge method: represents the electron transfer situation when the same element is converted from reactants to products before and after the reaction.

(1)Basic steps

(2) Precautions

①The arrows and tails must correspond to atoms of the same element whose valence changes.

② Must indicate "gain" or "lost".

③The number of electrons gained and lost in the reduced substance and the oxidized substance is conserved.

Redox reaction PPT, part 4: meeting standards in class and improving quality

1. The essence of redox reaction is ()

A． The valence of elements changes

B. Oxygen gain and loss in reaction

C． There is a gain or loss of electrons or a shift of electrons during the reaction.

D． New substances are produced after the reaction

2. Which of the following statements about redox reactions is correct ()

A． The valence of elements increases and decreases before and after the redox reaction

B. There must be gains and losses of oxygen before and after the redox reaction

C． The process of realizing the change of Fe3＋→Fe2+ must be an oxidation reaction

D． Reactions that increase the valence of an element are reduction reactions

A: The key to judging the concept of redox reaction is to grasp whether the valence of the elements changes during the reaction. Any change in valence must be due to a redox reaction, but it does not necessarily involve the gain or loss of oxygen. When the valence increases, an oxidation reaction occurs, Fe3+ is converted into Fe2+, and when the valence of iron decreases, a reduction reaction occurs. ]

Keywords: Free download of PPT courseware for high school chemistry compulsory course 1 from the People's Education Press, download of oxidation-reduction reaction PPT, .PPT format;

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Update Time: 2024-07-04

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