"Multicomponent Air" Air and Water PPT Courseware

Description

"Multicomponent Air" Air and Water PPT Courseware

learning target

Experiment to measure the oxygen content in the air

1. Red phosphorus combustion experimental phenomena, text expressions, and conclusions

2. Reasons for the small experimental results

3. The key to successful experiment

What happens when red phosphorus burns in the air?

Red phosphorus burns, emits heat, produces a large amount of white smoke, and generates phosphorus pentoxide.

Research experiment: Determining the amount of oxygen in the air

1. Connect the instrument and check the air tightness.

2. Put a small amount of water in the gas collecting bottle and use rubber bands to divide the remaining space into five equal parts.

3. Clamp the latex tube with a spring clamp, ignite excess red phosphorus, quickly insert it into the bottle, and tighten the cork.

4. When the gas collecting bottle cools to room temperature, open the spring clamp and observe the phenomenon.

【Experimental phenomena】

① Red phosphorus burns, emits heat, and produces a large amount of white smoke.

② After opening the water stop clamp, water enters the air collecting bottle along the conduit, accounting for about 1/5 of the air volume in the bottle.

think about it

1. What is the role of water?

Absorb heat, cool down, and reduce pressure to prevent the gas from expanding due to heat and popping the rubber plug.

2. What is the function of spring clip?

Prevent gas from escaping from the pipe opening due to thermal expansion

3. What is the purpose of releasing excess red phosphorus in the combustion spoon?

Fully consume the oxygen in the gas cylinder

4. After the red phosphorus extinguishing device is cooled and the spring clip is opened, why will water enter about 1/5 of the volume of the gas collecting bottle?

Because the red phosphorus burns and consumes the oxygen in the bottle to form a solid, the gas in the gas collecting bottle decreases and the air pressure becomes smaller, which is less than the external atmospheric pressure. Under the action of the external atmospheric pressure, water enters the gas collecting bottle; and because oxygen accounts for about 10% of the air 1/5 of the volume, so the water enters 1/5 of the air volume in the gas collecting bottle.

High School Entrance Examination Link

The device shown in the picture below can be used to measure the oxygen content in the air. Before the experiment, add a small amount of water to the gas collecting bottle and mark it. Which of the following statements is incorrect ( )

A. There must be an excess of red phosphorus during the experiment

B. Use spring clamps to clamp the latex tube before igniting the red phosphorus.

C. Open the spring clip immediately after the red phosphorus goes out

D. The final volume of water entering the bottle is approximately the volume of oxygen

think

1. What would our world look like if there was no air in the world we live in?

2. The air is all around you. Can you describe its physical properties?

3. Is air a single substance? What are its main components?

Class exercises

1. Calculated by volume, the most abundant gas in the air is ( )

A oxygen B nitrogen

C carbon dioxide D rare gas

2. The volume of oxygen in 100 liters of air is approximately ( )

A 78 liters B 78% C 21 liters D 21%

3. The volume ratio of oxygen to nitrogen in the air is approximately ( )

A 4:1 B 1:4 C 1:5 D 5:1

4. Pure substances and mixtures

Pure substance: composed of a substance

Such as: N2, O2, CO2, P, P2O5, H2O

Mixture: Made up of several substances

Such as: air, sea water, river water, mineral water, etc.

Pure substances can be represented by special chemical symbols. For example, nitrogen, oxygen, and carbon dioxide can be represented as N2, O2, CO2, etc. respectively.

Class exercises

1. Which of the following substances is pure ( )

A A rare gas separated from the air

Part B frozen distilled water

C salt water

D 75% medicinal alcohol

2. Among the following groups of substances, the former is a single substance and the latter is a mixture ( )

A. Nitrogen Distilled water B. iron ore salt water

C. Hydrogen CaCO3 D． carbon dioxide air

3. Which of the following water is a pure substance ( )

A mineral water B tap water C river water D ice-floating water

3. Air pollution and its prevention

1. Harmful substances in the air

Harmful gases: sulfur dioxide (SO2), carbon monoxide (CO), nitrogen dioxide (N02)

Smoke (respirable particulate matter)

2. Three major types of pollution

SO2, NO2, etc. → acid rain

Freon, etc.→Ozone Hole

Increased CO2 content →greenhouse effect

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For more information about the "Air and Water Multi-Component Air" PPT courseware, please click the Air and Water ppt Multi-Component Air ppt tag.

"Multicomponent Air" Air and Water PPT Courseware 3:

"Multicomponent Air" Air and Water PPT Courseware 3 1. Composition of Air [Think about it]: What is air made of? In order to understand the composition of air, many scientists have devoted themselves to research in this area, such as Swedish chemist Scheele and British chemist Priest.

"Multicomponent Air" Air and Water PPT Courseware 2:

"Multicomponent Air" Air and Water PPT Courseware 2 Thoughts 1. If there was no air in the world we live in, what would our world look like? 2. The air is all around you. Can you describe its physical properties? 3. Air is a single...

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Update Time: 2024-11-24

This template belongs to Chemistry courseware Hunan Education Edition Ninth Grade Chemistry Volume 1 industry PPT template

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