Why can iron rust and why does iron rust?

Iron rusts when left for a long time. Iron is susceptible to rust, not only because of its chemical activity, but also because of external conditions. Moisture is one of the substances that makes iron rust easily.

However, the presence of water alone does not rust iron, and only when the oxygen in the air is dissolved in the water, the oxygen reacts with the iron in the presence of water to form something called iron oxide, which is rust. Rust is a brownish-red substance, it is not as hard as iron, it can easily fall off, and after a piece of iron is completely rusted, the volume can expand by 8 times. If the rust is not removed, the spongy rust is particularly easy to absorb water, and the iron will rot faster.

To remove rust, you can shovel it off with various tools or soak it in an acidic solution to dissolve it. After removing the rust, the surface of the iron must be treated, coated with a layer of lead, and then painted; Or plating it with other metals that don't rust easily. A more radical approach is to add some other metals to the iron to make a stainless alloy.

The stainless steel we are familiar with is an alloy made by adding a little nickel and chromium to the steel.

The main causes of iron rust are air oxidation and electrochemical corrosion. As a result of an oxidation reaction with oxygen in the air, metal oxides, known as rust, are formed on the surface. If the metal contains more impurities, these impurities will form a chemical galvanic battery with the metal, and electrochemical corrosion will occur, thereby oxidizing the metal to form metal oxides.

2fe+o2+2h2o=2fe（oh）2

4fe（oh）2+o2+2h2o=4fe（oh）32fe（oh）3=fe2o3+3h2o

It can be understood that iron and oxygen are catalyzed by water to form iron oxide.

Iron oxide is the component of the rusty part of the iron after it rusts.

Iron rust conditions.

1. The air is moist.

2. The iron surface is in contact with the air.

Iron reacts chemically with oxygen in the air and rusts.

To be precise, the alloy of iron is oxidized in the humid air and rusts. Pure iron is difficult to rust in this case.

The principle is: pig iron and steel can be regarded as an alloy of iron and carbon, and oxygen absorption corrosion mainly occurs in humid air, that is, the galvanic cell formed by iron and carbon is first generated by Fe(OH)3, and gradually loses water to form rust (the main component is Fe2O3·NH2O), which is fluffy and absorbs water, and further corrodes the inner layer of iron, and finally makes the whole iron completely become Fe2O3.

Pour! The chemical change has become iron oxide.

Do you know why iron rusts?

The surface is easily oxidized to iron oxide.

Do you know why iron rusts?

Iron is susceptible to rust, not only because of its chemical activity, but also because of its external conditions. Moisture is one of the conditions that rust iron. Chemists prove:

Iron is placed in absolutely waterless air and does not rust for several years. However, the presence of water alone does not rust iron. If a piece of iron is placed in a boiled, airtight bottle of distilled water, the iron will not rust.

It turns out that iron rusts only when oxygen acts at the same time as water. In addition, carbon dioxide in the air dissolves in water, which can also cause iron to rust. The composition of rust is very complex, mainly iron oxide, iron hydroxide and basic iron carbonate.

Iron rusts because iron undergoes a chemical reaction under the action of oxygen and water. When the iron surface comes into contact with water and oxygen, the water molecules and oxygen molecules will undergo redox reactions with the iron surface to form a thin layer of iron oxide (Fe2O3·NH2O), which is often referred to as rust. The process of rust formation can be represented by the following reaction formula:

4fe + 3o2 + 6h2o → 4fe(oh)3fe(oh)3 → feo(oh) →fe2o3·nh2o + 3h2o

The reason for the rusting of iron is because iron has strong oxygen philophilia and is susceptible to oxidation. The formation of rust not only reduces the aesthetics of iron, but also leads to corrosion and damage to iron. In order to avoid rusting of iron, some measures can be taken, such as applying anti-rust paint, galvanizing, electrophoretic coating, etc., to isolate the iron from air and water, thereby preventing oxidation and corrosion of iron.

The reasons why iron will disappear when buried in the soil are as follows:

Iron is a relatively active metal, buried in the underground soil, it is easy to combine with the air and moisture in the soil to form iron hydroxide and iron oxide, this process is called rust. The mixture of iron hydroxide and iron oxide is loose and porous, and the volume expands about 7 times, which is called rust.

Cracks in the soil caused by volume expansion contribute to the continuous immersion of water and gas; Due to the looseness of rust, it is convenient for metal iron to continuously contact the oxidation and rust of water and gas, so a vicious circle, over time, metal iron no longer exists, and rust molecules slowly spread through soil cracks. So there is no trace of metallic iron. However, iron ions remain in the surrounding soil forever in a different form.

A commonly used method to prevent iron from rusting

1. Composition alloy method.

Adding some other elements to iron to change the internal structure of iron, such as adding chromium, nickel and other metals to ordinary steel to make stainless steel, greatly increases the rust resistance of steel products.

2. Coating protective layer method.

Coating mineral oil, paint or firing enamel, spraying, etc., such as: cars, buckets, etc. are often painted; The machine is often coated with mineral oil, etc.

3. Electroplating method.

The surface of iron products is plated with a layer of metal that is not easy to rust, such as zinc, tin, chromium, nickel, etc. These metal surfaces form a dense oxide film, which prevents iron products from rusting in contact with water, air and other substances.

4. Use chemical methods to form a dense oxide film.

A dense and stable oxide film is formed on the surface of iron products by chemical methods to prevent rust of iron products.

5. Keep the iron surface clean.

Keeping the surface of iron products clean and dry is also a good way to prevent iron products from rusting.

Why does iron rust? The main reason is due to the chemical reaction of iron with oxygen. When iron comes into contact with oxygen and water vapor in the air, the oxygen in the oxygen undergoes an oxidation reaction with the iron, forming an oxide of iron, commonly known as rust.

First of all, rust is mainly composed of iron oxide and hydrate next to the sedan group. Iron oxide is an oxidation product of iron, which has a reddish-brown or orange-yellow appearance. In a humid environment, water further promotes rust formation because it can provide oxygen and ions that allow for a more rapid oxidation reaction.

In addition, the formation of rust can also be considered as an electrochemical process. When iron comes into contact with an electrolyte in water, an anode and cathode region is formed on the iron surface. The iron ions on the anode are oxidized to iron ions and release electrons, while the oxygen on the cathode accepts electrons and reacts with water molecules to produce hydroxide ions.

These iron ions and hydroxide ions combine with each other to form rust.

It is important to note that iron rusting is a gradual process that continuously damages the surface of the iron, making it fragile and eventually leading to the breakage of the iron. In order to prevent iron from rusting, various measures can be taken, such as applying anti-rust coatings, electroplating, etc., to block the contact between iron and air and water. In addition, keeping the environment dry and avoiding exposure to moisture is also an effective way to slow down iron rust.

When iron reacts with oxygen in the air, it produces an oxide of iron, also known as rust. The chemical equation for iron rusting can be expressed by the following reaction formula:

4fe + 3o2 → 2fe2o3

In this equation, iron (Fe) reacts with oxygen (O2) to form ferric oxide (Fe2O3) remains, also known as rust.

Iron rust is a common chemical phenomenon known as oxidative corrosion of iron. When iron comes into contact with oxygen and water, an oxidation reaction occurs, resulting in the oxide of iron, which is commonly referred to as rust. The specific chemical equation is as follows:

4fe + 3o2 + 6h2o → 4fe(oh)3

In this reaction, iron (Fe) reacts with oxygen (O2) and water (H2O) to form iron (III) hydroxide (Fe(OH)3), which is known as rust.

It is important to note that the rusting of iron is a complex process that also involves electrochemical reactions and the formation of different forms of iron oxides. The above equation is just a simplified representation of the reaction.

Iron and oxygen rust when they encounter water or moisture in the air.

Rust is a very common chemical compound whose scientific name is iron oxide (Fe2O3) that rusts when iron and oxygen react in the presence of water or moisture in the air, and green rust occurs when iron reacts with chloride in the underwater environment.

The process of rusting is a combustion reaction similar to fire, when in contact with oxygen, iron reacts with oxygen to form rust, however, unlike fire, the reaction is much slower and does not produce flames. There are certain factors that can speed up the rusting process, such as water that accelerates the reaction, and salt which can also increase the speed of the rusting process.

Do you know why iron rusts?

Iron is one of the most common objects we see, so why does iron rust? There are many things in our lives: such as the iron part under the desk, the sliding door, etc., like the inner shell of the car made of iron. In the scrap metal yard, there are piles of yellow layers of rust.

We have seen a lot of rust in our daily life, the new bicycle we bought did not rust, and after a period of use, some parts of the bicycle rusted, what can be done to slow down the rust of iron? Let's do an experiment! Take two glasses, fill cup A with enough salt water so that all the iron or nails can be submerged in the salt water, and put half of the salt water in cup B so that half of the iron objects are placed in the salt water, and the other half is in contact with the air.

After a few days, if you look closely, you will find that the rust rate of iron iron is obviously much faster than that of iron iron tools.

What's going on? It turns out that the reasons for rust rust are: 1. Iron may be easy to rust when placed outside the damp, but it is not so easy to put it in a dry place!

Painted or plated iron is not prone to rust, while "bare" iron in the air is prone to rust. 2: Iron rust is a complex process, iron rust is related to contact with oxygen, moisture and various acids and alkalis in the air, iron is related to contact, and iron has a chemical reaction when it is in contact with relevant gases or liquids.

Rust is a dark red substance, and it is an easily detachable object...

Do you know why iron rusts?

This is because iron reacts with oxygen and water molecules in the air and oxidizes to form ferric oxide, also known as rust.

Rust is formed when iron is oxidized with water dissolved. This means that if there is no water vapor in the air, or if there is no water at all, or if there is no dissolved oxygen in the water, rust will not form. When a drop of rain falls on the surface of a piece of shiny iron, the drop remains clean for a short time.

However, it was not long before the iron and oxygen in the water began to coalesce to form iron oxide, or rust. The water droplets will turn reddish and the rust will be suspended in the water. When the water droplets evaporate, the rust remains on the surface, forming a reddish layer of rust.

Once rust is formed, it expands even in dry air. This is because coarse rust tends to condense the water vapor in the air, it absorbs the water vapor and stores it, which is why it is much easier to prevent iron rusting than to prevent rust from expanding.