Gdz in chemistry 8. Relationships between units of physical quantities

Key words: Chemistry 8th grade. All formulas and definitions, symbols of physical quantities, units of measurement, prefixes for designating units of measurement, relationships between units, chemical formulas, basic definitions, briefly, tables, diagrams.

1. Symbols, names and units of measurement
some physical quantities used in chemistry

2. Relations between units of physical quantities

3. Chemical formulas in grade 8

4. Basic definitions in grade 8

• Atom- the smallest chemically indivisible particle of a substance.
• Chemical element a certain type of atom.
• Molecule- the smallest particle of a substance that retains its composition and Chemical properties and made up of atoms.
• Simple substances Substances whose molecules are made up of atoms of the same type.
• Complex Substances Substances whose molecules are made up of different types of atoms.
• The qualitative composition of the substance shows what atoms it consists of.
• The quantitative composition of the substance shows the number of atoms of each element in its composition.
• Chemical formula- conditional record of the qualitative and quantitative composition of a substance by means of chemical symbols and indices.
• Atomic mass unit(amu) - a unit of measurement of the mass of an atom, equal to the mass of 1/12 of a carbon atom 12 C.
• mole- the amount of a substance that contains the number of particles equal to the number of atoms in 0.012 kg of carbon 12 C.
• Avogadro constant (Na \u003d 6 * 10 23 mol -1) - the number of particles contained in one mole.
• Molar mass of a substance (M ) is the mass of a substance taken in an amount of 1 mol.
• Relative atomic mass element A r - the ratio of the mass of an atom of a given element m 0 to 1/12 of the mass of a carbon atom 12 C.
• Relative molecular weight substances M r - the ratio of the mass of a molecule of a given substance to 1/12 of the mass of a carbon atom 12 C. The relative molecular mass is equal to the sum of the relative atomic masses of the chemical elements that form the compound, taking into account the number of atoms of this element.
• Mass fraction chemical element ω(X) shows what part of the relative molecular weight substance X falls on this element.

ATOMIC-MOLECULAR STUDIES
1. There are substances with a molecular and non-molecular structure.
2. There are gaps between the molecules, the dimensions of which depend on the state of aggregation of the substance and temperature.
3. Molecules are in continuous motion.
4. Molecules are made up of atoms.
6. Atoms are characterized by a certain mass and size.
At physical phenomena Molecules are preserved, while chemical ones, as a rule, are destroyed. Atoms in chemical phenomena rearrange, forming molecules of new substances.

THE LAW OF CONSTANT COMPOSITION OF A SUBSTANCE
Each chemically pure substance of molecular structure, regardless of the method of preparation, has a constant qualitative and quantitative composition.

VALENCE
Valency is the property of an atom of a chemical element to attach or replace a certain number of atoms of another element.

CHEMICAL REACTION
A chemical reaction is a process in which another substance is formed from one substance. Reagents are substances that enter into a chemical reaction. Reaction products are substances that are formed as a result of a reaction.
signs chemical reactions:
1. Release of heat (light).
2. Color change.
3. The appearance of a smell.
4. Precipitation.
5. Gas release.

• chemical equation- recording a chemical reaction using chemical formulas. Shows what substances and in what quantity react and are obtained as a result of the reaction.

LAW OF CONSERVATION OF MASS
The mass of substances that entered into a chemical reaction is equal to the mass of substances formed as a result of the reaction. As a result of chemical reactions, atoms do not disappear and do not appear, but their rearrangement occurs.

The most important classes of inorganic substances

Summary of the lesson “Chemistry Grade 8. All formulas and definitions.

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The Chemistry Resource Book for Grade 8 Gabrielyan is a collection of ready-made homework assignments, including solved problems, calculated reaction equations taken from study guide Gabrielyan O.S., which is the classical basis for the study of chemistry in the 8th grade of Russian secondary schools.

Reshebnik in chemistry grade 8 Gabrielyan O.S. 2013-2019

Tasks and reaction equations in a chemistry course are not easy practical tasks which not all students can complete the first time. Eighth graders may experience particular difficulties when preparing homework: in the 8th grade, students are given a fairly large amount of work to do at home, which does not allow them to waste much time preparing each subject.

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Answers of the GDZ textbook on chemistry for grade 8 Gabrielyan

At present, the program of secondary schools in Russia is compiled on the basis of the textbook by Gabielyan O.S., published by the Drofa publishing house in 2013.

The textbook consists of an introductory part (6 paragraphs) and 5 main chapters that cover such important topics as:

1. The structure of the atom and the atomic compound of chemical elements;
2. Simple substances, their properties;
3. Mixtures of substances and solutions;
4. Ion exchange reactions;
5. Redox processes.

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GDZ in chemistry for grade 8 Gabrielyan is a solution book or a collection of ready-made homework assignments, solved examples and problems, calculated reaction equations. It is compiled on the basis of a chemistry textbook for eighth graders, compiled by the honored Russian scientists- Gabrielyan O.S.

Answers to questions in chemistry grade 8 Gabrielyan - help to an eighth grader

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GDZ in chemistry for grade 8 Gabrielyan O.S. - the main sections of the textbook 2013.

All ready-made online answers to the chemistry solution book for grade 8 were compiled on the basis of the textbook Gabrielyan O.S., which was published in the second edition in 2013 under the stamp of the Drofa publishing house.

The book contains five thematic chapters that cover:

1. Atom structure and process atomic compound chemical elements;
2. Essence simple substances, their properties and the main changes occurring in them;
3. Mixtures of substances and solutions;
4. Ion exchange reactions and redox processes.

All sections of the textbook are supported by practical tasks and exercises that allow you to effectively learn the material.

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