About the amount of high school chemicals, the amount of high school chemicals

It is stipulated that under the standard condition, the volume of all gases of 1mol is, that is, it is usually expressed in VM, which is called the molar volume of gas. The quantity that is usually used to find a substance is n, n = v vm

For example, the molar mass of oxygen (O2) is 16 x 2 = 32, and the molar mass of hydrogen (H2) is 1 x 2 = 2, which is actually the relative molecular mass. n = m / m

Chemical calculations are actually very simple, and if you really want to figure it out, you can find a high school 1 book, or you can find it on the Internet.

Ah, as long as you see that the gas is xxmol l. You have to know how many mols he has.

Molar mass. It's normal to be confused at first.。。 Then I understood it spontaneously. Don't be afraid, don't be afraid

In other words, you should first treat it as a relative *** Xu

In fact, if the third year of junior high school is not necessary, don't rush to learn these for the time being, it's easy to make mistakes if you don't understand it.

It is the volume of 1 mol of gas under standard conditions, and no matter what kind of gas, if the chemical equilibrium is not considered, 1 mol is it.

We said that it is estimated that it is not as good as a textbook, so let's read it for ourselves. Electronic textbook, people's education version.

The textbook explains in great detail, including the principles and derivation process. It's much more convenient than us typing.

It refers to the volume of 1 mol of gas in the standard case (STP, 0 degrees Celsius, 1 atmosphere). This is only valid for gases, and neither solids nor liquids can be used to calculate moles.

For example, under STP.

Not under STP.

Rather, mol

When doing the question, you just need to grasp the main relationship.

Molar number = mass Molar mass (the numerical value is the same as the molecular weight).

The amount of chemicals in high school is explained as follows:

1. The quantity of matter is one of the seven basic physical quantities in the International System of Units, and it is the same as the concepts of "length", "mass", "time", etc., and is the overall noun of a physical quantity.

2. The unit is mole (mol), referred to as mole, and the symbol is (n).

3. The quantity of a substance is the ratio of the number of particles (n) (e.g., molecules, atoms, etc.) contained in a substance to Avogadro's constant (na), that is, n=n na.

4. The quantity of matter is a physical quantity, which represents a collective containing a certain number of particles, and the number of particles contained in a collective of 1mol particles is the same as the number of carbon atoms contained in carbon 12).

Molar mass. 1mol: The approximate value is the molar mass (m) unit g mol (formula m=m n).

1. Definition: The mass of a substance (the mass of 1mol of a substance) is called molar mass, that is, the relative atomic mass of 1mol of the substance is equal to the value of molar mass. The relationship between the quantity (n), mass (m), and molar mass (m) of a substance is:

n=m/m。

The mass of a mol particle in grams is numerically equal to the relative atomic mass (Ar) or relative molecular mass (MR) of the particle. (The value of molar mass is the same as that of the formula).

Relationship: w=(c*m) (1000*)100%. Expansion: c=(1000·w· )m.

High school chemical substance quantity related concepts:

1.The amount of matter.

1) Concept: A physical quantity that indicates the number of particles contained in a substance.

2) Symbol: n

3) Unit: mol

2.Moles. (1) Concept: Mole is a unit of quantity of matter, and every 1 mol of substance contains Avogadro's constant structural particles.

2) Symbol: mol

3) Description: When describing the amount of a substance (using moles), the name of the substance particle must be indicated, not the macroscopic substance name.

Common microscopic particles are: molecules, atoms, ions, electrons, protons, neutrons, or a specific combination of them.

When there is only one microscopic particle of some substances, its name can be omitted.

3.Avogadro's constant.

1) Meaning: Experimentally determine the number of carbon atoms in 12G12C.

2) Symbol: na

3) Unit: mol

4) Note: The benchmark for NA is the number of atoms in 12g of carbon-12.

12c is not only the reference object of moles, but also the reference object of relative atomic mass Na is an experimental value, which is often used as a calculation at this stage.

Pay attention to the difference between na and na.

4.Molar mass.

1) Concept: The quantity of a substance per unit of substance, the mass of a substance.

2) Symbol: M

3) Unit: g·mol-1

4) Description: Scope of use: aAny kind of microscopic particle bPure or notRegardless of the state of matter.

Comparison with formulas.

Comparison with the mass of 1mol of substance.

5.Molar volume of gas.

1) Concept: The volume of a gas per unit of substance.

2) Symbol: VM

3) Unit: l·mol-1

4) The molar volume of the gas under standard conditions.

Standard condition ATM i.e.

Ideal gas: aNot about the size, but about the quality.

b.Molecular interactions are not counted.

Molar volume of gas under standard conditions: approx.

5) Factors influencing the volume size of a substance:

The size of the particles that make up the substance (the nature of the substance).

The magnitude of the distance between structural particles (temperature and pressure are determined together).

The number of structural particles (the size of the amount of matter).

6.The amount of concentration of the substance.

1) Concept: The concentration of a solution is expressed by the amount of substances dissolved in a unit volume of solution.

2) Symbol: c

3) Unit: mol·l-1

4) Description: The quantity concentration of a substance is the volume concentration of the solution.

A solute in solution can be either a pure substance or a mixture, or it can refer to an ion or molecule.

The amount of a chemical substance in the first high:

1. Take out any volume of solution from the quantity concentration solution of a certain substance, the amount and concentration of the substance remain unchanged, but the amount of solute substance is different with the change of the volume of the solution.

2. At the same temperature and pressure, any gas in the same volume contains the same number of molecules.

3. The scope of application of the molar volume of the gas is a gaseous substance, which can be a single gas or a mixed gas.

4. The quantity of matter is measured by microscopic particles.

5. The mass of a substance per unit of substance is called the molar mass of the substance.

The selection of volumetric flasks must indicate the specifications, which should be equal to the volume of the solution being prepared.

If not, a volumetric flask slightly larger than this volume should be selected, such as a 500mL volumetric flask should be selected for the preparation of 500mL of 1mol·L-1 NaCl solution, if 480mL of the above solution is required, because there is no 480mL volumetric flask, a 500mL volumetric flask should also be selected, and the amount of solute required for the 500mL solution should be calculated according to the preparation of 500mL solution.

The method of checking whether the volumetric flask is leaking before use is: inject a small amount of water into the volumetric flask, plug the glass stopper tightly, press and hold the stopper with your fingers, press the bottom of the bottle with the other hand to reverse the volumetric flask, observe whether there is liquid oozing out at the cork after a period of time, if there is no liquid seeping, put it right, rotate the glass stopper 180°, and then reverse the observation.

n The amount of a substance in mol moles.

m molar mass unit g mol gram per mole is the molar mass without a unit, and the value is the same.

na Afergadro's constant is the specific number of one mole.

m can represent the mass of an atom or something like that.

Once you understand the meaning, you will naturally forget it.

First of all: the unit of quantity of matter mole, abbreviated mole, symbol mol, n = n naThe mass possessed by a substance per unit of quantity is the molar mass, for example:

The molar mass of mg is 24g moli.e. numerically equal to its mass, 24, the quantity of matter (n) mass (m) and the molar mass mRelationship:

n=m/m., unit: m is g, m is g mol

So n is mol

For example: What is the amount of sulfuric acid?

Answer: n = result as: , the mass of sodium carbonate is? m = number of particles (n).

m denotes the mass of the substance, n denotes the quantity of the substance, and m denotes the molar mass m=n*m

c In the case of the same temperature, pressure and volume, the specific volume of any gas is the same, the number of solid molecules is also the same, and they are all diatomic molecules, and the number of solid atoms is also the same.

Both are diatomic molecules, and the total number of molecules and atoms contained in a closed container of the same volume is equal. But the masses and the total number of electrons are not necessarily equal.

2 is correct.