What is the correct way to collect air

In general, there are two main methods: the evacuation method and the drainage method.

1.Emptying method: It is divided into upward emptying and downward emptying, and upward emptying method.

It is suitable for collecting gases with a density greater than air, and its principle is to use dense gases to make them denser than air.

Small gases are extruded, such as carbon dioxide is collected.

Gas. The downward emptying method is suitable for collecting gases with a lower density than air, as opposed to upward emptying, which uses a gas with a density smaller than air to squeeze the air upwards, such as collecting hydrogen.

Applicable instruments: alcohol lamps, iron frames, gas collection cylinders, wooden blocks, gas generating devices, etc.

Since the air is expelled, the air collected is not pure. Therefore, it is generally only necessary to collect gases that are easily soluble in water, but the operation is more difficult than discharge.

The water gas collection method is simple.

2. Drainage method: From the knowledge of physics, it can be known that if it is reversed into a gas collection cylinder filled with a certain liquid (short in and long out), it is not easy to dissolve in the liquid, and it will not have a chemical reaction with the liquid.

of gases. The liquid in it can be discharged and the container can be filled with the gas, according to which the gas can be collected directly by discharging some liquid by using the gas collection cylinder.

Merit. Drainage gas collection method.

It is a conventional method of collecting gas in the laboratory, which has the advantages of high purity, sufficient collection, no need to be full, less waste, and less pollution than the exhaust air method for gas collection.

Shortcoming. There is also a limited amount of gas that can be collected, and it is not possible to collect gases that are soluble in water. The gas has disadvantages such as large water content and inconvenient operation.

Precautions. 1.Before collection, check the airtightness of the device, that is, hold the test tube with your hand and observe the water surface to see if there are bubbles coming out; Or use an alcohol lamp to heat it up slightly, and immediately remove it to see if there is a section of water in the catheter.

If the above conditions are present, the device is well airtight. 2.When heating the gas, always remove the catheter first, and then remove the alcohol lamp, otherwise it will gasp, causing the test tube or flask to burst.

3.If the gas needs to be dried, it cannot be collected by the drainage method, but by the exhaust air method.

Such as the preparation of potassium permanganate.

Collect oxygen.

Place the bottle upside down to collect the air.

The question was how to collect air, but the answer was how to collect oxygen. Air and oxygen are not the same.

What are the ways to collect gas?

Summary. <>

Respiratory, combustion, and other uses. The air has compressible energy, and the air after the air compressor does mechanical work to shrink its own volume and increase the pressure is called compressed air. Compressed air is an important power source.

Respiratory, combustion, and other uses. The air has compressible energy, and the air after the air compressor does mechanical work to make Xinghui itself shrink in size and increase pressure is called compressed air. Compressed air is an important power source.

Extended information: Compressed air power refers to an automobile power system powered by bent and simple high-pressure compressed air, mainly in the car to install ultra-high pressure gas tank as an energy storage device, the high-pressure gas tank is connected to the high-pressure variable air motor through the control valve and accelerator pedal and lifts the drive system of the car. Compressed air is the second largest power energy source after electricity, and it is a process gas source with a variety of purposes, and its application range covers petroleum, chemical industry, metallurgy, electric power, machinery, light industry, textile buried shed pants, automobile manufacturing, electronics, food, medicine, biochemistry, national defense, scientific research and other industries and departments.

Gases that cannot be collected by the air exhaust method are:

a. h2b. co2

c. nod. o2

Answer: The air exhaust method is also a method of collecting gases. The air exhaust method is used for gases that do not react with the components in the air, and the density is very different from that of air (such as H2, CO2) The upward air exhaust method is used for gases that are denser than air The downward air exhaust method is used for gases that are less dense than air Note that the outlet pipe or inlet pipe needs to be inserted into the bottom of the bottle, and the air exhaust method is not suitable for toxic and harmful gases.

For example, dioxygen carries brightened sulfur) The following ** is also very important Upward Argument Wide Air Exhaust Method (Relative Molecular Mass is Greater than Air Huaiqiao, i.e., 29) Can Produce Oxygen Carbon Dioxide Downward Exhaust Air Method (Relative Molecular Mass is Less Than Air, i.e., <29).

Evacuation and drainage methods.

1. Emptying method: divided into upward emptying and downward emptying, the upward emptying method is suitable for collecting gases with a density greater than air, and its principle is to use dense gases to squeeze out gases that are less dense than air, such as collecting carbon dioxide gas. The downward emptying method is suitable for collecting gases with a density smaller than air, and the opposite of upward emptying is to use a gas with a density smaller than air to squeeze the air upwards, such as the collection of hydrogen suitable instruments

Alcohol lamps, iron stands, gas collection cylinders, wooden blocks, gas generators, etc., collect impure air because they are used to remove air. Therefore, it is generally only necessary to collect gases that are easily soluble in water, but it is easier to operate than the drainage high-macro gas collection method. 2. Drainage method:

From the knowledge of physics, it can be seen that lead Qi is injected into a gas cylinder filled with a certain liquid in a reverse direction (short in and long out) of a gas that is not easily soluble in the liquid and does not react chemically with the liquid. Then the liquid in it can be discharged, and the container can be filled with the gas, (using the principle of pressure) according to this principle, the gas can be directly used to collect the gas by discharging some liquid.

Take an empty bottle, wash it, close the cap, and the air sample will be collected in the bottle.

Due to the strong attraction of the earth, 80% of the air is concentrated in an average of 15 kilometers above the ground.

In this range you can use mobile phones, simple and convenient.

First take an appropriate container such as a glass bottle, fill it with water, take it to the place where the air needs to be sampled and analyzed, open the lid to pour the water out, collect the air and close the lid. The air in the bottle is a sample of the local air.

That plastic bag, put it in a bag, just tie it tightly.

Oxygen is collected by the upward exhaust air method.

Oxygen is not easily soluble in water and its density is greater than that of air, so it can be collected by the drainage method and the upward air exhaust method, so the answer is: c

1. Drainage method, suitable for insoluble in water, and the density is not much different from air, or toxic gas;

2. The upward exhaust air method is suitable for the collection of gases with a density greater than that of Xiaoxiao air and no toxicity;

3. The downward air exhaust method is suitable for gases with a density smaller than air and no toxicity.

It's generally these three methods that are wild.