Topic 3 Production of Oxygen

3Production of Oxygen

In the laboratory, oxygen is often produced by heating potassium permanganate, decomposing hydrogen peroxide or heating potassium chlorate

Potassium permanganate is a dark purple solid, which can be decomposed by heat to produce oxygen, and at the same time produce potassium manganate and manganese dioxide: Potassium permanganate to potassium manganate + manganese dioxide + oxygen

In addition to generating oxygen by heating potassium permanganate, oxygen is usually generated in the laboratory by decomposing hydrogen peroxide. Hydrogen peroxide can decompose to release oxygen at normal temperature, but when hydrogen peroxide is used to release oxygen, a small amount of manganese dioxide is usually added.

In experiment (1), since the hydrogen peroxide solution decomposed slowly at room temperature and released very little oxygen, the sparked stick could not be re-ignited. In experiment (2), the stick was re-ignited because a small amount of manganese dioxide was added to the hydrogen peroxide solution to accelerate the decomposition. The reaction can be represented as follows:hydrogen peroxide to water + oxygen

In experiment (3), the experiment was repeated many times, each time only hydrogen peroxide was consumed, while manganese dioxide seemed to be inexhaustible. If you use a precision balance to weigh the mass of manganese dioxide before the experiment, wash and dry the manganese dioxide after the experiment, and weigh it again, you will find that its mass has not changed. Adding it to hydrogen peroxide solution can also accelerate the decomposition of hydrogen peroxide. This kind of substance that can change the chemical reaction rate of other substances in a chemical reaction, but its quality and chemical properties do not change before and after the reaction is called a catalyst (also called a catalyst). The role played by a catalyst in a chemical reaction is called catalysis. Copper sulfate solution, etc. also have a catalytic effect on the decomposition of hydrogen peroxide.

Catalysts are widely used in chemical production. Catalysts are used in the production of fertilizers, pesticides and various chemical raw materials.

Oxygen can also be produced in the laboratory by heating solid potassium chlorate mixed with manganese dioxide. In addition to producing oxygen, a substance called potassium chloride is also produced. Ethylene dioxide is also a catalyst for this reaction. The reaction can be represented as follows: Potassium chlorate to potassium chloride plus oxygen

You should know after finishing this topic

1.In a chemical reaction, a reaction in which one reactant produces two or more other substances is called a decomposition reaction.

2.Oxygen can be produced in the laboratory by heating potassium peroxide, decomposing hydrogen peroxide solution or heating potassium chlorate.

3.In a chemical reaction, a substance that can change the chemical reaction rate of other substances without changing its mass and chemical properties before and after the reaction is called a catalyst. Catalysts have important applications in production.