"Air and Oxygen" PPT download

Description

"Air and Oxygen" PPT download

Part One: Preparing Oxygen in the Laboratory

1. Use hydrogen peroxide (hydrogen peroxide) to produce oxygen

step:

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. Use drainage method to collect gas.

2. Produce oxygen by heating potassium permanganate crystals

step:

1. Check the air tightness of the device;

2. Add KMnO4 crystals to the test tube;

3. Put cotton in the mouth of the tube and connect the device;

4. Heating KMnO4 crystal;

5. Use drainage method to collect gas.

3. Use heated potassium chlorate to produce oxygen

step:

1. Check the air tightness of the device;

2. Add the mixture of KClO3 and MnO2 to the test tube;

3. Connect the device;

4. Heat the mixture of KClO3 and MnO2;

5. Use drainage method to collect gas.

Precautions:

Solid drugs are placed at the bottom of the test tube and should be smooth;

The iron clamp should be clamped about one-third away from the mouth of the test tube;

The mouth of the test tube is slightly lower than the bottom of the test tube;

If potassium permanganate is used to produce oxygen, put a ball of cotton at the mouth of the tube;

The water droplets on the outer wall of the test tube should be wiped dry;

Heating with external flame of alcohol lamp;

Only when continuous bubbles appear at the catheter port can the gas be collected;

At the end, the catheter should be removed from the sink and then the alcohol lamp should be extinguished.

Air and Oxygen PPT, Part 2: Combination Reactions and Decomposition Reactions

1. Combination reaction: a reaction in which one substance is produced from two or more substances.

2. Decomposition reaction: a reaction in which one substance produces two or more substances.

think:

When Xiao Zhang was heating potassium permanganate to produce oxygen in the laboratory, he discovered:

(1). The water in the sink was dyed purple.

(2) The test tube also broke.

Could you please help him analyze what are the possible reasons for the above two phenomena?

(1) There is no cotton (or too little) in the mouth of the test tube; the test tube is too tilted; it is heated too hard, etc.

(2) The water droplets on the outer wall of the test tube are heated without being wiped dry; the test tube is heated unevenly; at the end of the test, extinguish the alcohol lamp first and allow the water to be sucked back into the test tube, etc.

Air and Oxygen PPT, Part 3: Industrial Production Method of Oxygen

think:

1. Why are the methods of industrial oxygen production and laboratory oxygen production different?

2. What are the changes in the above two oxygen production methods?

Air and Oxygen PPT, Part 4: Classroom Exercises:

1. When hydrogen peroxide is decomposed to obtain oxygen, if manganese dioxide is not added, the result is ( )

A. Does not produce oxygen B. Produces oxygen very slowly

C. The final mass of oxygen produced decreases

D. The rate of oxygen production increases

2. When preparing oxygen in the laboratory, the collection method that can be used is ( )

A. Drainage method or upward air exhaust method B. Only drainage method can be used

C. Only the upward air exhaust method can be used

D. Drainage method or downward air exhaust method

Keywords: Zhejiang Education Edition eighth grade science PPT courseware for the second volume free download, air and oxygen PPT download, .PPT format;

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"Air and Oxygen" PPT courseware:

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"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: 2024-10-06

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