"The quantity of matter" is one of the seven basic physical quantities in the international system of units. When understanding the concept, it cannot be literally understood as the quality of matter or the quantity of matter. It is a special term and a physical quantity that represents the number of particles contained in a substance. And mole is the unit of the amount of _ _ substance, referred to as _ _ Mo _ _, with the symbol __mol__. "The amount of matter" only applies to _ _ microscopic particles. Because there are many kinds of particles that make up a substance, when a substance is represented by "the amount of substance", it is necessary to specify basic units, such as 1mol hydrogen atom, 1mol hydrogen molecule, 1mol hydrogen ion, or it can be expressed by chemical formula as 1molH and1mol hydrogen ion.
2. Evan Gardello constant (NA)
The number of carbon atoms contained in _ _ 0.0 12 _ KG 12C is called Avon Gadereau constant, that is, the number of molecules of any particle of 1mol. The symbol is __NA__, and the unit is 1/mol _ _.
Avo Gadereau constant is a very accurate value, and _ 6.02 * 10 … 23 _ is its approximate value. That is, na = _ 6.02 *10 ... 23 _ _.
3. The relationship between the number of substances (n) and the number of particles (n)
( 1)n=_N/NA__ .
[Inference] (2) 1mol Any substance contains __NA__ particles.
(3) The ratio of the number of particles is equal to the ratio of the quantity of _ _ _ _.
4. Molar mass
The concept of (1) molar mass;
The mass per unit of matter is called the molar mass of matter. The unit of molar mass is _ _ grams per mole _ _, and the symbol is g/mol _ _.
(2) Relationship between molar mass and molecular weight (i.e. relative molecular mass or relative atomic mass):
The molar mass is the _ _ _ type quantity of particles, and the unit is g/mol. For example, the molar mass of CO is _ 28g/mol _ _, which is equal to the relative molecular mass _ _.
(3) The molar mass, the mass of 1mol and the molecular weight are the same, but the units are different. For example, the molar mass of water is _ 18g/mol _ _, the mass of 1mol water is _ 18_g__, and the relative molecular mass of water is _ 18 _ _.
Verb (abbreviation for verb) molar volume of gas
1, the relationship between the volume of matter and microscopic particles
The volume of a substance depends on the number of _ _ _ _ _ _ _ _ _ _. 1mol The volume of different solid and liquid substances mainly depends on the size of _ _ _ _ _ _ _. The volume of 1mol gas mainly depends on the distance between gas molecules. At the same temperature and pressure, the distance between any gas particles can be regarded as _ _ _ _ _ _ _, so any gas with the same number of particles has the same volume _ _ _ _ _ _. In other words, at the same temperature and pressure, any gas with the same volume contains the same number of _ _ _ _ _ _ gas particles.
2. Molar volume of gas
(1) Concept: The volume of gas in a unit substance is called the molar volume of gas, with the symbol Vm and the mathematical expression VM = v/n.
_ _ _ _ _, in l/mol or m3/mol. Under standard conditions, the volume occupied by any _ _ gas __ 1__mol is _ _ 22.4L _.
(2) Analysis of the concept of gas molar volume under standard conditions.
A. Four conditions: temperature: _ 0 _ _℃; Pressure: 100 _ _ _ kPa; Benchmark: _ _ gas _ substance; Object: Any gaseous object
B. Conclusion: _ 22.4l
C. expression form: _ VM = 22.4 l _/mol _ _；;
D, unit: __l/mol__.
The quantity and concentration of intransitive verb substances
1, the quantity and concentration of substances are defined as:
The physical quantity of solution composition is expressed by the quantity of substance containing particles of solute B per unit volume of solution, which is called the quantity concentration of substance of solute B in mol/L..
Please note the following points:
(1) volume refers to the volume of the solution, not the volume of the solvent;
(2) Take out any volume of 1mol/L solution with the concentration of _ 1mol/l__. However, the amount of solute substances contained varies with volume.
2. Calculation of substance quantity and concentration
(1) defines the formula __ n=cV.
(2) Derived formula: c = n/v.
(3) dilution law: c (concentrated solution) v (concentrated solution) =c (dilute solution) v (dilute solution)
3. Preparation of the solution of the amount and concentration of the substance
(1) Required instruments _ volumetric flask _ _, _ glass rod _ _, _ rubber-tipped dropper _ _, _ _ balance _ _ beaker _, if the solute is liquid or concentrated solution, the tray balance and medicine spoon in the above instruments can be changed to _ measuring cylinder _.
(2) Preparation steps: _ _ Calculate _ _, _ _ weigh _ _, _ _ dissolve _ _, _ _ cool _ _, _ _ pipet _ _, _ _ constant volume _ _.
(3) Principle of error analysis: _ _ According to CB = nB/V, the error of preparing a solution with a certain substance concentration is caused by the substance amount nB of solute and the volume V of the solution. In error analysis, the key depends on how N and V change in the preparation process. When preparing a solution with a certain substance concentration, if nB is less than the theoretical value or V is greater than the theoretical value, the concentration of the prepared solution will be smaller. If nB is greater than the theoretical value, or V is less than the theoretical value, the concentration of the prepared solution will be greater. ______________。