"Composition of Air" Composition of air and matter PPT courseware 2

Description

"Composition of Air" Composition of air and matter PPT courseware 2

introduce doubt

What components are in the air? How to keep the air clean and fresh?

Air is the backbone of life for humans and all animals and plants, and it is also an important natural resource. Scientists used scientific inquiry methods to discover the composition of air.

learning target

1. Understand what components are in the air

2. Understand the properties and uses of nitrogen and rare gases

Sort out goal 1

What are the components in the air

1. Determination of oxygen content in air

Please tell the name of the instrument referred to by each serial number in the picture:

① Combustion key ② Tube

③Water stop clamp ④Gas collecting bottle

⑤Beaker

Conclusion: It is proved that about 1/5 of the volume of air in the bottle supports combustion, and 4/5 of the volume of gas does not support combustion. The gas that supports combustion is oxygen. The main component of the gas that does not support combustion is nitrogen. In addition, there are a small amount of other gases, rare gases, carbon dioxide, water vapor, etc.

Knowledge expansion

①What phenomena did you see when red phosphorus burned?

There is a lot of white smoke produced

②Why does the water in the beaker enter the gas collecting bottle after opening the water stop clamp?

The oxygen in the bottle is consumed, the air pressure decreases, and atmospheric pressure forces water into the bottle.

③Water enters the gas collecting bottle and accounts for about 1/5 of the bottle’s volume. What does this mean?

It shows that the volume of gas (i.e. oxygen) consumed by the combustion of red phosphorus accounts for about 1/5 of the volume of air in the bottle.

④What is the main content of the remaining 4/5 volume of gas?

Nitrogen

⑤What do you think is the key to the success of the experiment?

1. The air tightness of the device should be good;

2. The amount of red phosphorus must be sufficient;

3. After the red phosphorus is ignited, put it into the bottle quickly;

4. Wait until the temperature in the reaction bottle drops to room temperature and the water level in the bottle no longer rises, then read the volume of water entering the bottle.

Sort out goal 2

Properties and uses of nitrogen and noble gases

1. Properties and uses of nitrogen

What are the usual properties of nitrogen?

Chemically stable, it is difficult to react with other substances at room temperature, but it can react with certain substances under high temperature and high energy conditions.

What are the common uses of nitrogen?

Important raw materials for making nitric acid and fertilizers

Used as protective gas

Liquid nitrogen freezing anesthesia

Synthetic dyes, manufacturing explosives

Filling food with nitrogen to prevent corrosion

Practice expansion

1. In 100mL of air, oxygen accounts for approximately ( )

A.2.1kg B.21L

C.21g　D.21mL

2. Take out a bottle of drink from the refrigerator in summer. In the air, the outer wall of the bottle will be moist, indicating that the air contains ( )

A. Nitrogen

B． oxygen

C. water vapor

D． carbon dioxide

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"Composition of Air" PPT courseware on the composition of air and matter:

"Composition of Air" PPT courseware on the composition of air and matter. 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: 2024-06-26

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

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