78%

twenty one%

0.94%

0.03%

0.03%

Filling bulbs to extend service life, anti-corrosion, protective gas, freezer, nitrogen fertilizer production

Mountaineering, diving, medical, gas welding and other industries, can be used as rocket accelerant

Beacon lights, strong lights, flash lights, neon lights; helium-filled balloons

Common fire extinguishing agents; main raw materials for photosynthesis; manufacturing of dry ice and artificial rainfall

Oxygen consumption No gas generation Gas pressure in the device decreases

Mercury Oxygen → (heated) mercury oxide

Check the air tightness of the device

Put a small amount of water into the gas collecting bottle and mark it. and divide the space above the water surface into 5 equal parts

Tighten the spring clamp and add enough red phosphorus to the burning spoon

Ignite the red phosphorus, quickly insert the gas collection bottle, and tighten the stopper

After the reaction is completed, the device cools down before opening the spring clamp.

Red phosphorus burns with a yellow flame, releasing heat and producing white smoke.

When the spring clamp is opened after cooling to room temperature, the water in the beaker is sucked back into the gas collecting bottle. Moreover, the volume of water entering accounts for about 1/5 of the total volume of air in the bottle.

Oxygen accounts for about 1/5 of the total volume of air

Insufficient amount of red phosphorus

The device is leaking (such as the bottle stopper is not tightly plugged, etc.), allowing outside air to enter the bottle.

Open the spring clip before cooling to room temperature to reduce the volume of water entering the bottle.

After igniting the red phosphorus, when inserting the burning key, the cork was inserted too slowly. The air in the bottle expands due to heat and some of the air escapes

At the beginning of the experiment, there were no clamps or no spring clamps clamped

Under normal temperature and standard atmospheric pressure, oxygen is a colorless and odorless gas. Denser than air and not easily soluble in water, it becomes Light blue liquid, turns into light blue snowflake-like solid at about -218°C.

Provides breathing and supports combustion. Chemical properties are relatively active Put the wooden stick with sparks into oxygen, and the wooden stick will re-ignite. This phenomenon can be used to identify whether the gas is oxygen.

Put the small wooden stick with sparks deep into the gas collecting bottle. If If the wood sticks re-ignite, it proves that the gas is oxygen.

Air

oxygen

Water is added to absorb phosphorus pentoxide

Literal expression: red phosphorus oxygen → (ignite) phosphorus pentoxide Symbolic expression: P O₂→ (lit) P₂O₅ Chemical equation: 4P 5O₂= (ignite) 2P₂O₅

Air

oxygen

Literal expression: carbon oxygen → (ignite) carbon dioxide Symbolic expression: C O₂→ (ignite) CO₂ Chemical equation: ① Full combustion: C O₂= (ignition) CO₂ ②Incomplete combustion: 2C O₂= (ignition) 2CO

Air

oxygen

Add water: absorb sulfur dioxide and prevent air pollution.

Literal expression: sulfur oxygen → (ignite) sulfur dioxide Symbolic expression: S O₂→ (lit) SO₂ Chemical expression: S O₂ = (ignite) SO₂

Air

oxygen

Purpose

Literal expression: iron oxygen → (ignite) ferric oxide Symbolic expression: Fe O₂→ (ignite) Fe₃O₄ Chemical equation: 3Fe 2O₂= (ignition) Fe₃O₄

Text expression: KMnO₄→ (heating) potassium manganate manganese dioxide oxygen Symbolic expression: KMnO₄→(△)K₂MnO₄ MnO₂ O₂↑ Chemical equation: 2KMnO₄=(△)K₂MnO₄ MnO₂ O₂↑

Text expression: potassium chlorate → (manganese dioxide heating) potassium chloride oxygen Symbolic expression: KClO₃→(MnO₂△)KCl O₂↑

Literal expression: hydrogen peroxide → (manganese dioxide) water oxygen Symbolic expression: H₂O₂→(MnO₂)H₂O O₂↑

The density of gas is much different from the density of air

Gases cannot react with components in the air

Denser than air: upward air exhaust method

Less dense than air: downward air exhaust method

Gas is insoluble in water

Gases cannot react with water

A reaction in which two or more substances produce another substance. (Multiple Changes One)

A reaction in which one substance produces two or more other substances. (One becomes many)