Chemistry class

What's number of valence electrons?

The number of valence electrons is the number of electrons in the outermost shell of an atom. These electrons are the ones that are involved in chemical reactions, and their number is often used to predict the reactivity of an atom and its ability to form chemical bonds. In general, atoms with a small number of valence electrons are more reactive, while atoms with a larger number of valence electrons are less reactive. The number of valence electrons can be determined by looking at the periodic table of elements, which shows the number of electrons in the outermost shell for each element.

 

Tell me the color of some chemical marterial?

The color of a chemical substance is determined by the wavelengths of light that it absorbs and reflects. Different chemical substances can have different colors, depending on their chemical composition and structure. For example, copper sulfate is a blue crystalline solid, sodium chloride (table salt) is a white crystalline solid, and iron oxide (rust) is a red-brown powder. Some chemicals are colorless, such as water and ethanol, while others are brightly colored, such as the dyes used in food, clothing, and cosmetics. The color of a chemical substance can also change depending on its concentration, temperature, and the presence of other chemicals.

 

The chemical substance introduced during middle school

There are many different chemical substances that are introduced in middle school, as students begin to learn about the basics of chemistry. Some common examples include:

• Water (H2O): Water is a colorless, tasteless, and odorless liquid that is essential for life on Earth. It is made up of two hydrogen atoms bonded to one oxygen atom.
• Oxygen (O2): Oxygen is a colorless, tasteless, and odorless gas that makes up about 21% of the Earth's atmosphere. It is essential for respiration in plants and animals, and is required for the burning of fuel.
• Carbon dioxide (CO2): Carbon dioxide is a colorless, odorless gas that is produced by the burning of fossil fuels, the respiration of plants and animals, and the fermentation of sugars. It is a greenhouse gas that contributes to global warming.
• Salt (NaCl): Salt is a white crystalline solid that is made up of sodium and chlorine atoms. It is a common food seasoning, and is also used to preserve food and make soap.
• Acids and bases: Acids are chemicals that release hydrogen ions (H+) when they are dissolved in water, while bases are chemicals that release hydroxide ions (OH-) when they are dissolved in water. Acids and bases have different chemical properties and react with each other to form neutral compounds, such as salt and water.

These are just a few examples of the many chemical substances that are introduced in middle school. As students learn more about chemistry, they will encounter a wide range of chemical substances with different properties and uses.

https://www.bilibili.com/video/BV1wb411x78e?p=15  分子和原子

What construct the substance?

Substances are made up of atoms原子, molecules分子, or ions离子.

Atoms are the basic units of matter, and are made up of protons质子, neutrons中子, and electrons电子.

Molecules分子 are formed when two or more atoms combine chemically, and can be made up of atoms of the same element (such as oxygen molecules, O2) or different elements (such as water molecules, H2O).

Ions are atoms or molecules that have gained or lost one or more electrons, giving them a net positive or negative charge正负电荷. The number and arrangement of atoms, molecules, or ions in a substance determine its chemical composition and physical properties, such as its color, density密度, and melting and boiling points.

What does net positive mean?

Net positive means having a positive value after all deductions or negatives have been taken into account. For example, if a person has $100 and spends $50, their net positive balance would be $50.

In the context of ions, net positive means having a positive charge after gaining or losing electrons. Ions are atoms or molecules that have gained or lost one or more electrons, giving them a net positive or negative charge. For example, if an atom gains an electron, it becomes negatively charged and has a net positive charge. Similarly, if an atom loses an electron, it becomes positively charged and has a net negative charge.

 

Translate 微粒 to English

The Chinese word 微粒 (wēilì) can be translated into English as "particle" or "microscopic particle". It typically refers to a very small piece of matter, such as a molecule, atom, or subatomic particle. 微粒 can also be used to describe a very small amount of a substance, such as a tiny drop or a speck. In some contexts, it may be translated as "particulate" or "microscopic".

 

What construct microscopic particle?

Microscopic particles are made up of atoms, molecules, or ions. Atoms are the basic units of matter, and are made up of protons, neutrons, and electrons.

Molecules are formed when two or more atoms combine chemically, and can be made up of atoms of the same element (such as oxygen molecules, O2) or different elements (such as water molecules, H2O). Ions are atoms or molecules that have gained or lost one or more electrons, giving them a net positive or negative charge.

These microscopic particles are too small to be seen with the naked eye, but can be observed using a microscope or other scientific instruments. The properties of microscopic particles, such as their size, shape, and charge, determine their behavior and interactions with other particles.

 

What's the difference between the substance and microscopic particle?

A substance is a material that is made up of atoms, molecules, or ions that are chemically bonded together. Substances can be pure, such as water or oxygen, or can be a mixture of two or more substances, such as air or saltwater. Substances have specific properties, such as color, density, and melting and boiling points, that are determined by their chemical composition and structure.

Microscopic particles, on the other hand, are the individual atoms, molecules, or ions that make up a substance. These particles are too small to be seen with the naked eye, but can be observed using a microscope or other scientific instruments. Microscopic particles have properties such as size, shape, and charge that determine their behavior and interactions with other particles. For example, the microscopic particles of a substance can determine its solubility可溶性, reactivity, and other physical and chemical properties.

In summary, substances are made up of microscopic particles, and the properties of a substance are determined by the properties of its microscopic particles.

 

What's the definition of molecules in chemistry?

In chemistry, a molecule is a group of two or more atoms that are chemically bonded together. A molecule can be made up of atoms of the same element (such as oxygen molecules, O2) or different elements (such as water molecules, H2O). The atoms in a molecule are held together by chemical bonds, which are formed when electrons are shared between the atoms. The structure and arrangement of atoms in a molecule determine its chemical properties, such as its reactivity and solubility. Molecules can be observed using microscopes and other scientific instruments, but are too small to be seen with the naked eye.

在化学中，分子是指由两个或两个以上相同或不同元素组成的稳定化合物。分子是化学物质的最小单位，它具有特定的化学结构和性质。例如，水分子是由两个氢原子和一个氧原子组成的，它具有特定的分子式 H₂O。

分子是由原子组成的，它们通过电子的共享形成化学键，从而构成分子。分子的大小和形状取决于它的组成元素和它们之间的化学键的数量和类型。

分子在化学中起着重要的作用，它是化学反应的基本单位。例如，在水的合成反应中，氢分子和氧分子通过电子共享反应，形成水分子。分子也可以用来表示物质的分子式，从而确定物质的化学成分。

 

Why the white sugar disappeared when I put it into water? Try to explain it in chemistry

When you put white sugar (sucrose) into water, it appears to disappear because it dissolves in the water to form a homogeneous mixture. This process is called dissolution, and it occurs because the molecules of sugar are attracted to the molecules of water and become evenly distributed throughout the water. The resulting mixture has the same properties throughout, and no longer looks or behaves like sugar.

In chemistry, the solubility of a substance is the maximum amount of that substance that can dissolve in a given amount of solvent (such as water) at a specific temperature and pressure. The solubility of sugar in water is relatively high, so a large amount of sugar can dissolve in a given amount of water. When sugar is added to water, the water molecules surround and interact with the sugar molecules, breaking the attractive forces that hold the sugar molecules together. This allows the sugar molecules to move freely and become evenly distributed throughout the water, forming a solution.

In summary, when sugar is put into water, it dissolves and becomes evenly distributed throughout the water, forming a homogeneous mixture. This process is called dissolution, and it occurs because the molecules of sugar are attracted to the molecules of water and are able to move freely and become evenly distributed throughout the water.

 

The difference between white sugar and sucrose?

White sugar and sucrose are the same thing. "Sucrose" is the chemical name for the sugar that we commonly use to sweeten food and beverages饮料. It is a white, crystalline solid that is made up of molecules of the two simple sugars glucose葡萄糖 and fructose果糖. When sucrose is extracted from sugarcane甘蔗 or sugar beets甜菜 and purified, it is known as "white sugar." White sugar is the most common form of sucrose that is used in cooking and baking.

Sucrose is a disaccharide二塘, which means that it is made up of two simple sugars (glucose and fructose) that are chemically bonded together. When sucrose is dissolved in water, the water molecules interact with the sucrose molecules, breaking the bonds between the glucose and fructose molecules and releasing the individual sugar molecules into the water. This is why sugar dissolves in water and forms a homogeneous mixture.

In summary, white sugar and sucrose are the same thing. "Sucrose" is the chemical name for the sugar that we commonly use, while "white sugar" is the most common form of sucrose that is used in cooking and baking. Sucrose is a disaccharide made up of two simple sugars (glucose and fructose) that are chemically bonded together. When it is dissolved in water, the bonds between the simple sugars are broken and the individual sugar molecules are released into the water.

 

 Does it mean it's a chemical reaction instead of a physical reaction when sucrose dissolved in water?

均匀混合物（homogeneous mixture），又称均相混合物，是指不管提取该物质的哪一个部分，它的成分含量比例都是相同的混合物。

When sucrose (white sugar) dissolves in water, it forms a homogeneous mixture that has the same properties throughout. This process is called dissolution, and it is a physical process, not a chemical reaction.

A chemical reaction is a process in which atoms or molecules are rearranged to form new substances with different chemical properties. In a chemical reaction, bonds between atoms are broken and new bonds are formed, resulting in the formation of new chemical compounds. A chemical reaction is characterized by the release or absorption of energy, the formation of new substances, and the change in the composition of the reacting substances.

In contrast, a physical process is a change in the physical properties of a substance, such as its size, shape, or state, without a change in its chemical composition. Physical processes, such as dissolution, do not involve the formation of new substances or the change in the composition of the reacting substances. They are reversible, meaning that the original substances can be recovered by reversing the process.

In summary, when sucrose dissolves in water, it forms a homogeneous mixture without undergoing a chemical reaction. This process is a physical process, in which the sugar molecules are attracted to the water molecules and become evenly distributed throughout the water, without changing their chemical composition.

 

What does this mean "breaking the bonds between the glucose and fructose molecules"？

When sucrose (white sugar) dissolves in water, the water molecules interact with the sucrose molecules, breaking the bonds between the glucose and fructose molecules and releasing the individual sugar molecules into the water. This process is called dissolution, and it is a physical process, not a chemical reaction.

Sucrose is a disaccharide, which means that it is made up of two simple sugars (glucose and fructose) that are chemically bonded together. These bonds are called glycosidic bonds, and they are formed when the hydroxyl group (-OH) of one sugar molecule reacts with the anomeric carbon of another sugar molecule. This reaction produces a molecule of water and a molecule of sucrose, with the glucose and fructose molecules bonded together.

When sucrose dissolves in water, the water molecules surround and interact with the sucrose molecules. The water molecules are polar, meaning that they have a positive charge at one end and a negative charge at the other end. The positive end of the water molecule is attracted to the negative end of the sucrose molecule, and the negative end of the water molecule is attracted to the positive end of the sucrose molecule. This attraction causes the bonds between the glucose and fructose molecules to break, releasing the individual sugar molecules into the water.

In summary, "breaking the bonds between the glucose and fructose molecules" refers to the process of dissolving sucrose in water, in which the water molecules interact with the sucrose molecules and cause the bonds between the glucose and fructose molecules to break. This releases the individual sugar molecules into the water, forming a homogeneous mixture. This process is a physical process, not a chemical reaction, and it is reversible, meaning that the original substances can be recovered by reversing the process.

 

Does glycosidic bond belong to chemical bond? why breaking this bond, does not introduce chemical reaction?

A glycosidic bond is a type of chemical bond that is formed between two sugar molecules. It is a covalent bond, which means that it is formed when atoms share electrons in order to achieve a stable electronic configuration. In the case of a glycosidic bond, the hydroxyl group (-OH) of one sugar molecule reacts with the anomeric carbon of another sugar molecule, forming a molecule of water and a molecule of sucrose with the glucose and fructose molecules bonded together.

When sucrose (white sugar) dissolves in water, the water molecules interact with the sucrose molecules, breaking the bonds between the glucose and fructose molecules and releasing the individual sugar molecules into the water. This process is called dissolution, and it is a physical process, not a chemical reaction.

A chemical reaction is a process in which atoms or molecules are rearranged to form new substances with different chemical properties. In a chemical reaction, bonds between atoms are broken and new bonds are formed, resulting in the formation of new chemical compounds. A chemical reaction is characterized by the release or absorption of energy, the formation of new substances, and the change in the composition of the reacting substances.

In contrast, a physical process is a change in the physical properties of a substance, such as its size, shape, or state, without a change in its chemical composition. Physical processes, such as dissolution, do not involve the formation of new substances or the change in the composition of the reacting substances. They are reversible, meaning that the original substances can be recovered by reversing the process.

In summary, a glycosidic bond is a type of chemical bond that is formed between two sugar molecules. When sucrose dissolves in water, the water molecules interact with the sucrose molecules and cause the bonds between the glucose and fructose molecules to break. This process is a physical process, not a chemical reaction, and it does not involve the formation of new substances or the change in the composition of the reacting substances. It is reversible, meaning that the original substances can be recovered by reversing the process. Breaking the glycosidic bond between the glucose and fructose molecules is an essential part of the process of dissolving sucrose in water, but it does not introduce a chemical reaction. Instead, it allows the sugar molecules to move freely and become evenly distributed throughout the water, forming a homogeneous mixture.

 

How can I reverse the sucrose dissolved in water?

To reverse the process of dissolving sucrose in water, you can simply heat the water until it reaches its boiling point. As the water boils, the increased temperature and pressure will cause the sugar molecules to leave the water and form solid sucrose crystals again. The process of crystallization is the opposite of dissolution, and it occurs when the dissolved sugar molecules lose their freedom of movement and form a solid crystal structure.

To reverse the process of dissolving sucrose in water, follow these steps:

1. Fill a pot with water and place it on the stove火炉.
2. Heat the water until it reaches its boiling point (100°C or 212°F).
3. As the water boils, the increased temperature and pressure will cause the dissolved sugar molecules to leave the water and form solid sucrose crystals.
4. As the crystals form, they will settle to the bottom of the pot.
5. Once most of the sugar has crystallized, you can remove the pot from the heat and let it cool.
6. Once the water has cooled, you can carefully pour it off, leaving the sucrose crystals behind.

Alternatively, you can also reverse the process of dissolving sucrose in water by adding more sugar to the water. As you add more sugar, the concentration of sugar in the water will increase, and the excess sugar molecules will begin to form solid sucrose crystals. This process is called oversaturation过饱和, and it occurs when the amount of dissolved sugar in the water exceeds its solubility溶解度 limit. The excess sugar molecules will then form solid crystals that will settle to the bottom of the container.

In summary, to reverse the process of dissolving sucrose in water, you can either heat the water until it reaches its boiling point, or add more sugar to the water until the concentration of sugar exceeds its solubility limit. Both of these methods will cause the dissolved sugar molecules to leave the water and form solid sucrose crystals. The resulting solid sucrose crystals will be the same as the original sugar that was dissolved in the water, and can be used in the same way. This process is reversible, meaning that the original substances can be recovered by reversing the process.

 

Can we dry the water of  homogeneous mixture under the sun to reverse the dissolution?

It is not possible to reverse the process of dissolving sucrose in water by drying the water under the sun. When sucrose (white sugar) dissolves in water, it forms a homogeneous mixture that has the same properties throughout. This process is called dissolution, and it is a physical process, not a chemical reaction.

In a chemical reaction, atoms or molecules are rearranged to form new substances with different chemical properties. In a chemical reaction, bonds between atoms are broken and new bonds are formed, resulting in the formation of new chemical compounds. A chemical reaction is characterized by the release or absorption of energy, the formation of new substances, and the change in the composition of the reacting substances.

In contrast, a physical process is a change in the physical properties of a substance, such as its size, shape, or state, without a change in its chemical composition. Physical processes, such as dissolution, do not involve the formation of new substances or the change in the composition of the reacting substances. They are reversible, meaning that the original substances can be recovered by reversing the process.

When you dry the water of a sucrose solution under the sun, you are removing the water from the solution, but you are not changing the chemical composition of the sucrose molecules. The sucrose molecules will remain dissolved in the remaining water, and will not form solid crystals. This means that drying the water under the sun will not reverse the process of dissolution, and the original sucrose will not be recovered.

In summary, it is not possible to reverse the process of dissolving sucrose in water by drying the water under the sun. This method will not change the chemical composition of the sucrose molecules, and will not cause them to form solid crystals. To reverse the process of dissolution, you can either heat the water until it reaches its boiling point, or add more sugar to the water until the concentration of sugar exceeds its solubility limit. These methods will cause the dissolved sucrose molecules to leave the water and form solid crystals, which can be recovered and used in the same way as the original sugar.

 

What will I get if I evaporate all the water of the solution by sun?

If you evaporate all the water from a sucrose solution by exposing it to the sun, you will be left with a concentrated sucrose solution. This solution will have a higher concentration of sucrose than the original solution, and will be more viscous and syrupy in consistency. The process of evaporating the water from the solution will not change the chemical composition of the sucrose molecules, and will not cause them to form solid crystals.

When sucrose (white sugar) dissolves in water, it forms a homogeneous mixture that has the same properties throughout. This process is called dissolution, and it is a physical process, not a chemical reaction. In a physical process, the properties of the substance, such as its size, shape, or state, are changed without changing its chemical composition.

When you evaporate the water from a sucrose solution by exposing it to the sun, you are removing water molecules from the solution, but you are not changing the chemical composition of the sucrose molecules. The sucrose molecules will remain dissolved in the remaining water, and will not form solid crystals. As the water evaporates, the concentration of sucrose in the solution will increase, and the solution will become more viscous粘稠的 and syrupy糖浆般粘稠的 in consistency.

In summary, if you evaporate all the water from a sucrose solution by exposing it to the sun, you will be left with a concentrated sucrose solution. This solution will have a higher concentration of sucrose than the original solution, and will be more viscous and syrupy in consistency. The process of evaporating the water from the solution will not change the chemical composition of the sucrose molecules, and will not cause them to form solid crystals.

 

But why it is possible to get the salt from the  homogeneous mixture of salt and water under sun?

When salt (sodium chloride) dissolves in water, it forms a homogeneous mixture that has the same properties throughout. This process is called dissolution, and it is a physical process, not a chemical reaction.

In a physical process, the properties of the substance, such as its size, shape, or state, are changed without changing its chemical composition. When salt dissolves in water, the water molecules surround and interact with the salt molecules, breaking the attractive forces that hold the salt molecules together. This allows the salt molecules to move freely and become evenly distributed throughout the water, forming a solution.

When you evaporate the water from a salt solution by exposing it to the sun, you are removing water molecules from the solution, but you are not changing the chemical composition of the salt molecules. The salt molecules will remain dissolved in the remaining water, and will not form solid crystals. As the water evaporates, the concentration of salt in the solution will increase, and the solution will become more viscous and syrupy in consistency.

However, when the water has almost completely evaporated, the salt molecules will begin to come out of solution and form solid crystals. This process is called crystallization, and it is the opposite of dissolution. As the water evaporates, the concentration of salt in the solution will increase, and the excess salt molecules will lose their freedom of movement and begin to form solid crystals. The resulting solid crystals of salt will be the same as the original salt that was dissolved in the water, and can be collected and used in the same way.

In contrast, when sucrose (white sugar) dissolves in water, it forms a homogeneous mixture that has the same properties throughout. This process is called dissolution, and it is a physical process, not a chemical reaction. When you evaporate the water from a sucrose solution by exposing it to the sun, you are removing water molecules from the solution, but you are not changing the chemical composition of the sucrose molecules. The sucrose molecules will remain dissolved in the remaining water, and will not form solid crystals. This means that evaporating the water from a sucrose solution by exposing it to the sun will not produce solid sucrose crystals, as is the case with salt.

In summary, it is possible to obtain solid salt crystals from a salt solution by evaporating the water from the solution by exposing it to the sun. This process is called crystallization, and it is the opposite of dissolution. As the water evaporates, the concentration of salt in the solution will increase, and the excess salt molecules will lose their freedom of movement and begin to form solid crystals.

In contrast, evaporating the water from a sucrose solution by exposing it to the sun will not produce solid sucrose crystals, as the sucrose molecules will remain dissolved in the remaining water.

 

Why the sucrose did not crystal when water is completely evaporated?

When sucrose (white sugar) dissolves in water, it forms a homogeneous mixture that has the same properties throughout. This process is called dissolution, and it is a physical process, not a chemical reaction. In a physical process, the properties of the substance, such as its size, shape, or state, are changed without changing its chemical composition.

When you evaporate the water from a sucrose solution by exposing it to the sun, you are removing water molecules from the solution, but you are not changing the chemical composition of the sucrose molecules. The sucrose molecules will remain dissolved in the remaining water, and will not form solid crystals. This means that even if you completely evaporate the water from a sucrose solution by exposing it to the sun, you will not be able to obtain solid sucrose crystals.

The reason why sucrose does not crystallize when the water is completely evaporated is that sucrose has a high solubility in water. This means that a large amount of sucrose can dissolve in water at a given temperature and pressure. When the water is completely evaporated, the concentration of sucrose in the remaining solution will be very high, and the sucrose molecules will not have enough energy to overcome the attractive forces that hold them together and form solid crystals. Instead, they will remain dissolved in the remaining water, forming a concentrated syrup-like solution.

In contrast, salt (sodium chloride) has a lower solubility in water than sucrose. This means that a smaller amount of salt can dissolve in water at a given temperature and pressure. When the water is completely evaporated from a salt solution, the concentration of salt in the remaining solution will be high enough to cause the excess salt molecules to overcome the attractive forces that hold them together and form solid crystals. This process is called crystallization, and it is the opposite of dissolution. The resulting solid crystals of salt will be the same as the original salt that was dissolved in the water, and can be collected and used in the same way.

In summary, the reason why sucrose does not crystallize when the water is completely evaporated is that sucrose has a high solubility in water, and a large amount of sucrose can dissolve in water at a given temperature and pressure. When the water is completely evaporated, the concentration of sucrose in the remaining solution will be very high, and the sucrose molecules will not have enough energy to overcome the attractive forces that hold them together and form solid crystals. Instead, they will remain dissolved in the remaining water, forming a concentrated syrup-like solution.

 

What do you mean by  remaining solution, since I supposed that I have evaporate all of the water molecules

When you evaporate the water from a sucrose or salt solution by exposing it to the sun, you are removing water molecules from the solution. However, it is not possible to evaporate all of the water molecules from the solution. This is because water has a high vapor pressure, which means that it easily evaporates at a given temperature and pressure. When water evaporates, it turns into water vapor, which is a gas. However, the process of evaporation is not 100% efficient, and some water molecules will remain dissolved in the solution, even after most of the water has evaporated.

The term "remaining solution" refers to the liquid mixture that is left behind after most of the water has evaporated from the original solution. This remaining solution will still contain some water molecules that were not able to evaporate, as well as the dissolved sucrose or salt molecules. The concentration of sucrose or salt in the remaining solution will be higher than in the original solution, as the water molecules that were able to evaporate will have taken some of the sucrose or salt molecules with them.

In summary, the term "remaining solution" refers to the liquid mixture that is left behind after most of the water has evaporated from the original solution. This remaining solution will still contain some water molecules that were not able to evaporate, as well as the dissolved sucrose or salt molecules. The concentration of sucrose or salt in the remaining solution will be higher than in the original solution.

 

What's the solubility of sucrose and salt?

The solubility of a substance is the maximum amount of that substance that can dissolve in a given amount of solvent at a given temperature and pressure. The solubility of sucrose (white sugar) in water is approximately 180 grams per 100 milliliters of water at room temperature (20-25 degrees Celsius). This means that 180 grams of sucrose can dissolve in 100 milliliters of water at room temperature, forming a clear, transparent solution.

The solubility of salt (sodium chloride) in water is approximately 36 grams per 100 milliliters of water at room temperature (20-25 degrees Celsius). This means that 36 grams of salt can dissolve in 100 milliliters of water at room temperature, forming a clear, transparent solution.

In summary, the solubility of sucrose in water is approximately 180 grams per 100 milliliters of water at room temperature, while the solubility of salt in water is approximately 36 grams per 100 milliliters of water at room temperature. This means that sucrose has a higher solubility in water than salt, and a larger amount of sucrose can dissolve in water at a given temperature and pressure.

 

What is the milliliters ?

1L=1000mL 1000毫升=1000立方厘米 =1立方分米

1毫升=1西西(cc).

1毫升=1立方厘米

A milliliter (mL) is a unit of volume that is commonly used to measure the volume of liquid substances. It is a metric unit that is equal to one thousandth of a liter (L), and is often used to measure the volume of small amounts of liquid, such as a drop of water or a spoonful of medicine.

One milliliter is equivalent to 0.001 liters, and is also equivalent to 0.000001 cubic meters. It is a very small unit of volume, and is commonly used to measure the volume of small objects or quantities of liquid. For example, a standard dropper bottle of medicine might contain 20 mL of liquid, which is equivalent to 20 thousandths of a liter.

In summary, a milliliter (mL) is a unit of volume that is commonly used to measure the volume of liquid substances. It is a metric unit that is equal to one thousandth of a liter, and is often used to measure the volume of small amounts of liquid.

 

Please explain "Molecules is the smallest particle that can keep the chemical substance properties unchangeable".

分子是保持物质化学性质的最小粒子

A molecule is the smallest unit of a chemical substance that retains the properties of that substance. A molecule is made up of one or more atoms that are bonded together. The atoms in a molecule can be the same or different, and the properties of the molecule will depend on the type of atoms it is made of and the way they are bonded together.

For example, the molecule of water (H2O) is made up of two hydrogen atoms and one oxygen atom. The properties of water, such as its color, odor, and ability to dissolve other substances, are determined by the type of atoms it is made of and the way they are bonded together. The molecule of water is the smallest unit of water that retains these properties, and if you break the molecule of water into smaller units, such as atoms or ions, the properties of water will change.

In contrast, a microscopic particle is a small particle that can be seen under a microscope, but is too small to be seen with the naked eye. A microscopic particle can be a single molecule, or it can be a group of molecules that are bonded together. The properties of a microscopic particle will depend on the type of molecules it is made of and the way they are bonded together.

In summary, a molecule is the smallest unit of a chemical substance that retains the properties of that substance. A molecule is made up of one or more atoms that are bonded together, and the properties of the molecule are determined by the type of atoms it is made of and the way they are bonded together. In contrast, a microscopic particle is a small particle that can be seen under a microscope, but is too small to be seen with the naked eye.

 

Is there any substance construct by atom directly instead of molecules?

Yes, there are some substances that are made up of atoms directly, without being organized into molecules. These substances are known as elemental substances, and they are the simplest and purest forms of matter.

An elemental substance is a pure substance that is made up of only one type of atom. For example, the element carbon is made up of only carbon atoms, and the element oxygen is made up of only oxygen atoms. Elemental substances cannot be broken down into simpler substances by chemical means, and they retain their chemical and physical properties regardless of the amount or form they are in.

Elemental substances can exist in different physical states, depending on their temperature and pressure. For example, the element carbon can exist in three different physical states: solid (as graphite or diamond), liquid (as lamp black or soot), or gas (as carbon dioxide or methane). The properties of an elemental substance will vary depending on its physical state, but the chemical properties of the substance will remain the same, regardless of its physical state.

In summary, an elemental substance is a pure substance that is made up of only one type of atom, and cannot be broken down into simpler substances by chemical means. Elemental substances can exist in different physical states, and their properties will vary depending on their physical state, but their chemical properties will remain the same.

 

What's the smallest construction metric unit of substance?

The smallest metric unit of substance is the mole. The mole is the basic unit of measurement in the International System of Units (SI) for the amount of a substance. It is used to measure the number of atoms, molecules, or other units of a substance.

One mole of a substance is equal to the number of atoms, molecules, or other units in 12 grams of carbon-12 (C-12), which is a stable isotope of carbon. This number is called the Avogadro constant, and is approximately 6.022 x 10^23. This means that one mole of any substance contains 6.022 x 10^23 atoms, molecules, or other units of that substance.

The mole is a very large unit, and is usually used to measure the amount of a substance in grams, kilograms, or other units of mass. For example, one mole of oxygen molecules (O2) weighs approximately 32 grams, while one mole of sodium chloride (NaCl) crystals weighs approximately 58.5 grams.

In summary, the mole is the smallest metric unit of substance, and is used to measure the number of atoms, molecules, or other units of a substance. One mole of a substance is equal to the number of atoms, molecules, or other units in 12 grams of carbon-12, and is approximately 6.022 x 10^23. The mole is a very large unit, and is usually used to measure the amount of a substance in grams, kilograms, or other units of mass.

 

But why someone said the smallest construction metric unit is molecules?

 

It is true that some people may refer to molecules as the smallest construction metric unit of substance. This is because a molecule is the smallest unit of a chemical substance that retains the properties of that substance. A molecule is made up of one or more atoms that are bonded together, and the properties of the molecule are determined by the type of atoms it is made of and the way they are bonded together.

For example, the molecule of water (H2O) is made up of two hydrogen atoms and one oxygen atom bonded together. The properties of water, such as its color, odor, and ability to dissolve other substances, are determined by the type of atoms it is made of and the way they are bonded together. The molecule of water is the smallest unit of water that retains these properties, and if you break the molecule of water into smaller units, such as atoms or ions, the properties of water will change.

In contrast, an atom is the smallest unit of a chemical element that retains the properties of that element. An atom is made up of a nucleus, which contains protons and neutrons, surrounded by electrons. The number of protons in the nucleus determines the chemical element, and the number of electrons determines the chemical properties of the atom.

In summary, a molecule is the smallest unit of a chemical substance that retains the properties of that substance. A molecule is made up of one or more atoms that are bonded together, and the properties of the molecule are determined by the type of atoms it is made of and the way they are bonded together. In contrast, an atom is the smallest unit of a chemical element that retains the properties of that element.

 

The difference between substance and element in chemistry.

In chemistry, a substance is a material with a definite composition and properties. A substance can be a pure chemical element, such as gold or oxygen, or it can be a chemical compound, such as water or salt. Substances can exist in different physical states, such as solid, liquid, or gas, and can undergo chemical reactions to form new substances with different properties.

An element is a pure substance that is made up of only one type of atom. For example, the element carbon is made up of only carbon atoms, and the element oxygen is made up of only oxygen atoms. Elements cannot be broken down into simpler substances by chemical means, and they retain their chemical and physical properties regardless of the amount or form they are in.

In summary, a substance is a material with a definite composition and properties, and can be a pure chemical element or a chemical compound. An element is a pure substance that is made up of only one type of atom, and cannot be broken down into simpler substances by chemical means. Elements are the building blocks of matter, and all substances are made up of one or more elements.

当我说物质的最小单位是分子时，我是指物质在典型条件下的最小单位。在一般情况下，物质是由分子构成的，而分子是由两个或两个以上相同或不同元素组成的稳定化合物。分子是化学物质的基本单位，它具有特定的化学结构和性质。

但是，在某些情况下，物质可能不是由分子构成的，而是由原子或其他结构构成的。例如，氧气在一些条件下可以是由大量单独的氧原子构成的，而不是分子氧。在这种情况下，氧原子可能是物质的最小单位。

什么情况下氧气由大量单独的氧原子构成？

氧气在一些条件下可以是由大量单独的氧原子构成的，而不是分子氧。这种情况通常发生在氧气受到高能量的破坏作用时，例如在某些化学反应中或在高温条件下。在这种情况下，氧气分子会被分解成单独的氧原子，这些氧原子就成为了氧气的最小单位。

例如，在燃烧反应中，氧气可以与燃料混合反应，产生热能和光能。在这种情况下，氧气分子会被燃料中的氢原子分解，产生单独的氧原子。同样在高温条件下，氧气也可能会分解成单独的氧原子。氧气分子的结构非常稳定，因此它们需要较高的能量才能被分解。当氧气在高温条件下经受高能量的破坏作用时，它们的分子结构就会受到破坏，导致它们分解成单独的氧原子。

总的来说，氧气在某些特定的条件下可能会分解成单独的氧原子，这些氧原子就成为了氧气的最小单位。但在大多数情况下，氧气是由分子氧构成的，而分子氧是由两个氧原子组成的。

The usage difference between keep and retain, why we used the term "retain properties" instead of "keep properties" in chemistry?

In general, the words "keep" and "retain" can be used interchangeably to mean to hold or maintain possession of something. However, there are some subtle differences in the way these words are typically used.

"Keep" is often used to refer to the act of holding onto something or maintaining possession of it over a period of time. For example, you might say "I need to keep this book for the rest of the week" or "I will keep this secret to myself." In these cases, "keep" emphasizes the act of continuing to possess something.

"Retain," on the other hand, is often used to refer to the ability or capacity to hold onto something, especially in the face of external forces that might cause it to be lost or dissipated. For example, you might say "this material retains its shape well" or "this substance retains its color when exposed to light." In these cases, "retain" emphasizes the ability to maintain something despite external factors.

In the context of chemistry, the term "retain properties" might be used to refer to a substance's ability to maintain its chemical and physical characteristics over time, despite exposure to external conditions that might otherwise cause it to change or degrade. For example, a substance might be said to "retain its solubility in water" if it continues to dissolve in water even when subjected to high temperatures or other conditions that might cause other substances to lose their solubility. In this case, "retain" is used to emphasize the substance's ability to maintain its properties despite external factors.

In summary, the words "keep" and "retain" are similar in meaning but can have slightly different connotations. "Keep" often emphasizes the act of maintaining possession, while "retain" often emphasizes the ability or capacity to maintain something despite external factors. 

In chemistry, the term "retain properties" is used to refer to a substance's ability to maintain its chemical and physical characteristics over time, despite exposure to external conditions that might otherwise cause it to change or degrade. This can include a substance's ability to maintain its physical form, color, solubility, reactivity, and other properties that are important for its identity and behavior in chemical reactions.

The use of the term "retain" in this context emphasizes the substance's ability to maintain its properties despite external factors that might otherwise cause it to change or lose those properties. This is an important concept in chemistry, as many substances can undergo changes in response to external conditions, and the ability to maintain properties can be a key factor in determining the suitability of a substance for a particular use or application.

In general, a substance that can "retain its properties" is considered to be more stable and reliable than a substance that cannot maintain its properties under the same conditions. This can be an important factor in the design and performance of chemical reactions, as well as in the selection of materials for various applications.

 

What happened when Iodine encounter starch?

Iodine does not react with starch by itself. However, when iodine is added to a solution of starch, the iodine molecules bind to the starch molecules, resulting in a blue-black color change. This is because the iodine molecules are large enough to fit between the starch molecules and interact with the electrons in the starch molecules, causing the color change. This reaction is often used in chemistry experiments as a way to test for the presence of starch.

 

Is it a chemical reaction or physical reaction between Iodine and starch?

The interaction between iodine and starch is a chemical reaction. A chemical reaction is a process in which the molecules of one or more substances are transformed into new substances with different properties. In the case of iodine and starch, the iodine molecules react with the starch molecules, resulting in a new substance with a different color.

In contrast, a physical reaction is a process in which the physical properties of a substance are changed without any change in the molecular composition. An example of a physical reaction is the melting of ice, which occurs when the temperature of the ice increases and causes it to change from a solid to a liquid state. The molecular composition of the ice remains the same, and only the physical properties, such as the temperature and state, are altered.

What's the name of the new generated substance?

When iodine reacts with starch, a new substance is formed, but it does not have a specific name. The reaction between iodine and starch is a simple one, in which the iodine molecules bind to the starch molecules, resulting in a blue-black color change. The exact composition of the resulting substance will depend on the exact conditions of the reaction, such as the concentration of the iodine and starch solutions, the temperature, and the presence of any other substances.

Why the new substance does not have a name?

The new substance formed when iodine reacts with starch does not have a specific name because it is a relatively simple and unimportant substance. In chemistry, substances are typically given names based on their chemical formulas or their properties. In the case of the reaction between iodine and starch, the exact composition of the resulting substance will vary depending on the conditions of the reaction, and it does not have any unique or noteworthy properties that would warrant giving it a specific name. Additionally, the substance is not commonly used or studied in chemistry, so there is no need to give it a name.

 

I apologize for any confusion. "H2O2+MnO2" is a chemical formula that represents a reaction between hydrogen peroxide (H2O2) and manganese dioxide (MnO2). In this reaction, the hydrogen peroxide oxidizes the manganese dioxide to produce oxygen gas and water, according to the following equation:

2H2O2 + 2MnO2 → 2O2 + 2H2O

This reaction is often used in chemistry experiments to demonstrate the production of oxygen gas. However, this formula does not have a corresponding translation in Chinese, as it is not a word or phrase in English. I hope this information is helpful. If you have any further questions, please don't hesitate to ask. I am here to assist you.

 

How small is molecules?

The size of molecules can vary greatly, depending on the type of molecule and its structure. In general, molecules are extremely small, with sizes on the order of nanometers (nm) or picometers (pm). A nanometer is one billionth of a meter, or about 10-9 meters, while a picometer is one trillionth of a meter, or about 10-12 meters. For comparison, a human hair is about 100,000 nanometers thick, while a water molecule is about 0.3 nanometers in diameter. In other words, molecules are extremely tiny, even compared to other microscopic objects. 

 

The characteristics of molecules include the following:

• Tiny: As mentioned previously, molecules are extremely small, with sizes on the order of nanometers (nm) or picometers (pm). This makes them invisible to the naked eye and requires the use of specialized instruments, such as microscopes, to observe them.

• Movable: Molecules are constantly in motion, due to the kinetic energy of their constituent atoms and molecules. This motion is known as molecular motion, and it allows molecules to move, rotate, and vibrate.

• Composed of atoms: Molecules are made up of atoms, which are the basic building blocks of matter. The arrangement and bonding of atoms within a molecule determine its chemical properties and behavior.

• Heterogeneous: Molecules can be composed of different types of atoms, resulting in a wide variety of chemical compounds and structures. This heterogeneity allows molecules to exhibit a wide range of physical and chemical properties.

• Reactivity: Molecules can undergo chemical reactions with other molecules, forming new substances and releasing or absorbing energy. This reactivity is a fundamental property of molecules and is the basis of many chemical processes and reactions.

• Electron distribution: The distribution of electrons within a molecule determines its chemical properties and behavior. Molecules can have different arrangements of electrons, resulting in different types of bonds and interactions with other molecules.

• Polar or non-polar: Molecules can be either polar or non-polar, depending on the distribution of their electrons. Polar molecules have a positive charge at one end and a negative charge at the other, while non-polar molecules have an equal distribution of charge. This property affects the solubility of molecules in different solvents and their interactions with other molecules.

 

Goodpasture syndrome is a chronic autoimmune disorder, which means that it is a long-term condition that cannot be cured. However, with appropriate treatment, the symptoms of Goodpasture syndrome can be managed and the progression of the disorder can be slowed.

Treatment for Goodpasture syndrome may include medications to suppress the immune system and prevent further damage to the lungs and kidneys. In some cases, procedures may be necessary to remove damaged tissue from the lungs or kidneys. The specific treatment plan will depend on the individual person and the severity of their condition.

While Goodpasture syndrome cannot be cured, it is possible to manage the symptoms and prevent further damage with appropriate treatment. It is important to work closely with a healthcare provider to develop a treatment plan that is right for you.

 

作者:Chuck Lu    GitHub