"Oxygen" The air around us PPT courseware 3

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"Oxygen" The air around us PPT courseware 3

1. Physical properties

Generally refers to color, state, smell, melting point, boiling point, hardness and density, whether it is soluble in water, etc.

(1) Colorless, odorless gas

(2) Denser than air

(3) Not easily soluble in water

2. Chemical properties

(1) Experiment 2-2

(Phenomena) When a piece of wood with sparks is put into oxygen, it will rekindle.

(Explanation that oxygen can support combustion)

Applications derived from Experiment 2-2:

Oxygen test method: Insert the wooden stick with sparks into the gas collecting bottle. If the wooden stick re-ignites, it proves that the bottle contains oxygen (this is the easiest way to distinguish air and oxygen)

1. First put the burning wood sticks into four gas bottles respectively. If the wood sticks burn more vigorously, the bottle with oxygen; the bottle with no change in burning condition is air; the ones that extinguish the wood sticks are nitrogen and carbon dioxide. 2. Pour a small amount of clear lime water into these two bottles. After shaking, the bottle of lime water that becomes muddy is carbon dioxide, and the bottle that remains basically unchanged is nitrogen.

(2) Experiment 2-3 Combustion of sulfur

Discussion: Charcoal and sulfur burn in air and in oxygen respectively. What does this mean?

Substances burn less violently in air than in oxygen, which shows that the combustion of substances mainly reacts with oxygen. The oxygen content in the air is only about 1/5, and the combustion reaction of substances is not as violent as in pure oxygen. This shows that the severity of the reaction is related to the concentration of oxygen.

Through the above experiments, ask students to compare and draw conclusions.

1. Combustibles burn much more violently in oxygen than in air.

2. Some substances that cannot burn in air can burn in oxygen, which shows that the chemical properties of oxygen are relatively active.

3. When a substance burns in the air, it actually reacts with the oxygen in it. Since the oxygen content in the air is relatively small, burning in the air is not as violent as in oxygen.

Please try to summarize the chemical properties of oxygen.

Chemical properties of oxygen: Oxygen is a gas with relatively active chemical properties. It has oxidizing properties, can support combustion, and can react with many substances. The higher the oxygen content, the more intense the combustion.

3. Combination reactions and oxidation reactions

chemical reaction:

(1) A reaction in which two or more substances produce one substance.

(2) Expression: A + B +...C

(3) Judgment basis: types of reactants and products. "One in many ways".

Oxidation reaction:

(1) The reaction between matter and oxygen.

(2) Judgment basis: Another substance in the reactant can provide oxygen element.

(3) Such as: carbon + oxygen carbon dioxide

Carbon + Copper Oxide Copper + Carbon Dioxide

Slow oxidation:

(1) The oxidation reaction that proceeds very slowly and is not easily noticed is called slow oxidation.

(2) Such as the respiration of animals and plants (beneficial), the brewing of wine and vinegar (beneficial)

The rotting of farmyard manure (favorable), the rotting of food (unfavorable)

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For more information about the PPT courseware "Oxygen in the Air Around Us", please click the Oxygen in the Air Around Us ppt tag.

"Air and Oxygen" PPT download:

"Air and Oxygen" PPT Download Part One: Preparing Oxygen in the Laboratory 1. Steps to produce oxygen using hydrogen peroxide (hydrogen peroxide): 1. Check the air tightness of the device; 2. Add MnO2 to the flask; 3. Connect the device; 4. Add H2O2 to the separatory funnel; 5..

"Air and Oxygen" PPT courseware:

"Air and Oxygen" PPT courseware Part 1: Composition of air 1. Prove that the air contains carbon dioxide: -----Air can make clear lime water turbid. 2. Proof that there is water vapor in the air: -----When ice is placed in a cup, water droplets appear on the wall of the cup. -----Anhydrous sulfur..

"Air and Oxygen" PPT:

"Air and Oxygen" PPT Part One: Properties of Oxygen 1. Observe the color and state of a bottle of oxygen. 2. Gently fan the mouth of the bottle with your hand to let a small amount of oxygen float into your nostrils and smell its smell. Oxygen is a ____color____odorous gas. Smell...

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Update Time: 2024-07-04

This template belongs to Chemistry courseware People's Education Press Ninth Grade Chemistry Volume 1 industry PPT template

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