What are the reasons for the failure of the wire combustion test in oxygen?

There are many reasons for the failure of the wire combustion experiment in oxygen, and it is enough to analyze it according to the conditions under which the wire burns in oxygen. Combustion failures can be caused by: low purity of oxygen in the gas collection cylinder; The surface temperature of the wire is low and the ignition point of the wire is not reached; The rust on the surface of the wire has not been removed.

It can be analyzed according to the burning conditions of the wire. Combustion requires combustibles to have a certain contact with oxygen, the more full the contact, the easier it is to burn, and the temperature must reach the ignition point of combustibles.

If the amount of oxygen collected is too small or the purity is too low, the wire may not burn; The wire is not preheated, and the temperature does not reach the ignition point; When the match is put into the gas cylinder before it is burned out, or when the wire rusts and contains paint on the surface, the wire may not burn, causing the experiment to fail;

The reason for the failure of the wire combustion experiment in oxygen is that the wire is not heated properly. The oxygen is not pure and does not meet the requirements of a certain concentration. Then the choice of iron wire is not suitable.

There must be a variety of reasons, it can be common that for example, the wire is too thick and too thick to burn, the second is not heated in place, so he will not burn when it goes deep into the oxygen, and the third is that the oxygen content is insufficient, and he will not burn.

The reason for the failure of the test is that the wire is too large, the flame temperature is too low, or the oxygen content is too low.

The oxygen is not pure and the temperature is not enough.

The reason for the failure is that the wire burns when it encounters oxygen.

Angels do not arise in the air. Than I thought of my task has eaten dirt.

In many cases, depending on the temperature, it is normal for people to burn completely.

It can be analyzed according to the combustion conditions of the iron wire Combustion requires combustibles to have a certain contact with oxygen, and the more full the contact, the easier it is to burn, and the temperature should reach the ignition point of combustibles;

If the amount of oxygen collected is too small or the purity is too low, the wire may not burn; The wire is not preheated, and the temperature does not reach the ignition point; When the match is put into the gas cylinder before it is burned out, or when the wire rusts and contains paint on the surface, the wire may not burn, causing the experiment to fail;

So the answer is: the rust on the wire has not been removed; The purity of oxygen is not high; The wire is not preheated (reasonably fine).

1.There is no water or a layer of fine sand in the gas cylinder, and the high-temperature product falls and bursts the gas cylinder when burning;

2.When burning, the high-temperature product splashes onto the wall of the bottle, causing the cylinder to burst.

3.The burning wire touched the inner wall of the gas collector cylinder, causing the cylinder to burst when heated, and so on.

1.There is no water or sand in the cylinder, and the high-temperature product falls and bursts the cylinder when burning.

2.When burning, the high-temperature product falls onto the wall of the cylinder, causing the cylinder to burst.

Because the cylinder is not filled with water or fine sand, the high temperature generated when the iron burns in oxygen causes the wall of the cylinder to burst.

1.Oxygen is not pure.

2.Do you put sand at the bottom of the bottle?

(1) The phenomenon of iron wire burning in oxygen is: violent combustion, sparks, generating black solids, and releasing a lot of heat;

2) The purpose of winding the iron wire into a spiral is to increase the contact area between the iron wire and oxygen, so that the iron wire burns more violently and the phenomenon is more obvious; Second, it is conducive to maintaining the temperature required for the burning of the iron wire, so that the iron wire continues to burn;

3) The purpose of lighting the match at the beginning of the experiment is to use the heat released by the match combustion to increase the temperature of the wire, reach the ignition point, and ignite the wire;

4) if oxygen is replaced with air, the reaction (cannot) proceed;

5) The conclusion that can be drawn from this experiment is that: combustibles usually burn more in oxygen than in air (violently); Substances that do not burn easily in the air do (burn) in oxygen

1) The phenomenon is a violent burning, and the sparks are radiating in all directions.

2) The purpose of winding the wire into a spiral is to increase the contact area between the wire and oxygen and increase the local temperature.

3) The purpose of lighting a match at the beginning of the experiment is to ignite the wire.

4) No, you can't. 5): Combustibles usually burn more violently in oxygen than in air; Substances that do not burn easily in the air (fill in "easy" or "not easily") can burn in oxygen.

Increase the contact area with oxygen, ignition, can't, violent, not easy, easy.

1 Releases a lot of heat, and Mars shines everywhere.

2 Increase the contact area with oxygen.

3 The match has a low ignition point and is easy to ignite (is it used to light an alcohol lamp......).4) No, you can't.

5 is more violent, not easy to burn, can be burned.

2. It is to increase the contact area.

3. It is convenient to trigger a reaction.

4) No, you can't. 5. Intense, not easy to burn.

The selected wire should be treated with sandpaper, and this change is a (physical) change.

The reason why the wire is wound in a spiral shape is (to increase the contact area with oxygen); The reason why a match is tied to the front end of the wire is (to bring the temperature to the ignition point of iron combustion); The reason why the bottom of the gas collection cylinder is pre-filled with a small amount of water or covered with a layer of fine sand (to prevent the resulting melt from splashing the bottom of the bottle) is the literal expression of the reaction (iron + oxygen ferric tetroxide, ignited above the arrow step), which is both an (oxidation) reaction and a (compound) reaction.

If oxygen is replaced with air, the chemical reaction (cannot proceed) because of the low concentration of oxygen.

1. Physical changes.

2. Increase the heating area with oxygen and ignite the wire to prevent the high-temperature melt from dripping and bursting the gas cylinder.

3. The wire burns violently, sparks scatters, radiates heat, and generates a black solid.

4. Iron + oxygen ---ignition) - ferric oxide chemical oxidation.

5. Iron cannot be burned in the air.

To correct a teaching error, not all iron cannot be burned in the air, but it will also burn when the contact area with the air reaches a certain level, and the iron powder can be burned in the air to form red iron oxide (ferric oxide).

Chemistry; Evenly heated; Heating and burning the wire; Prevent the beaker from being too high and bursting; The wire burns violently, emitting heat and emitting heat; Fe+O2 ---heating)--Fe3O4; Chemical combination; Oxidation; No; There is little oxygen in the air. That's what a coincidence, too, we learned.

(1) Instruments used in the experiment: gas collection cylinders, glass plates, crucible pliers;

2) The wire is silvery-white;

3) Chemical experiments should not only be carefully observed, but also the methods of observing experimental phenomena; Therefore, the answer is: burning violently, sparks are scattered, generating black solids, and emitting heat;

4) The iron wire is burned in oxygen to generate high-temperature ferric tetroxide, and if the product falls directly to the bottom of the bottle, it will burst the bottom of the bottle, and the bottom of the bottle should be filled with water or spread sand; According to the reactants and products, the chemical equation is accurately written, so the answer is: 3Fe+2O2

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Therefore, the answer is: (1) crucible pliers, gas collection cylinders, glass plates; (2) silvery-white; (3) Burning violently, the fire is shining, generating a black solid, and emitting a large amount of heat

4) To fill the bottom of the bottle with water or spread sand, the splashed melt bursts the bottom of the bottle, 3Fe+2O2 ignites

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Answer ba Heat the thin wire on the alcohol lamp first, so that the temperature of the wire pants is burned to the point where the grill is on fire, which is correct.

b. A small amount of water or sand is placed at the bottom of the gas collector cylinder to prevent the product from splashing and bursting the gas collector cylinder, so it is wrong.

The phenomenon of the burning of iron wire in oxygen includes: violent combustion, sparks, the formation of black solid nonsense standby, and the release of a large amount of heat.

Therefore c and d are correct. Therefore, choose B

a. Sulfur and iron both release heat when they are burned in oxygen, so the choice is correct;

b. Iron combustion generates solids, so the option is wrong;

c, are in the ignition of the condition to take the pants under the sail to react so pure block option wrong;

d. Iron combustion can not produce blue-purple fire to eliminate hail flames, so the option is wrong, so choose A

The combustion of a substance must meet the following three basic conditions:

1) Combustibles: Regardless of solids, liquids and gases, any substances that can react violently with oxygen or other oxidants in the air are generally combustible substances, such as wood, paper, gasoline, alcohol, gas, etc.

2) Combustibles: Substances that can help and support combustion are called combustibles. Generally refers to oxygen and oxidants, mainly referring to oxygen in the air. This oxygen is called air oxygen.

3) Ignition source: Any energy source that can cause the combustion of combustible substances is called an ignition source, such as open flame, friction, impact, electric spark, etc.

Only when the above three conditions are met can the substance be burned. For example, a stove can only be lit if it has three conditions: wood (combustible), air (combustible), and match (fire source).