Lesson simple and complex substances chemical element. Open lesson “Chemical elements. Simple and complex substances. Topic: "Simple and complex substances"

Lesson 7 Theme "Simple and complex substances. Relative atomic and molecular weights"

Purpose: the formation of the concept of "relative atomic mass" among students, relative

molecular mass"

Tasks: - to study the concepts: simple and complex substances, relative molecular weight; - learn how to calculate the relative molecular weight; determine by formulas simple and complex substances;

Solve problems independently using existing knowledge;

Develop the ability to analyze, compare, compare and generalize;

Equipment: PTHE

During the classes:

1. Introductory-motivational stage

a) organizational moment

b) mental attitude

2. Actualization of previous knowledge

Chemical workout.

The teacher shows cards with symbols of chemical elements, students name them.

TEST - checking the previously studied material (to check the answers, the neighbors in the desk change sheets of paper and put marks - mutual check)

Task 1: match .

1. Argentum 4. Silicium 7. Arsenicum 10. Ferrum

2. Aurum 5. Stannum 8. Stibium

3.Hydrargyrum 6.Plumbum 9.Cuprum

a) Ag; b) Cu; c) Fe; d) Sb; e) Sn; e) Hg; g)Pb; h) As; i) Si; j) Au .

3. Learning new material

Relative atomic mass (Ar) element is the ratio of the mass of an atom of a given element to 1/12 of the mass of a carbon atom; it is a dimensionless quantity.

For example: Ar (H 2) = 1 · 2 = 2

Ar (Cl 2) = 35.5 · 2 = 71

Relative molecular weight (Mr) substance is the sum of the relative atomic masses of the elements that make up the substance.

To group complex.

The guys in the notebook draw up a diagram (with the help of a teacher):

SUBSTANCES

simple complex

H 2 ,O 2 , N 2 , Cl 2 H 2 Oh, CO 2 ,H 2 SO 4 O

development of concepts - simple and complex substances

Relative molecular weight and its calculation (s independent work)

Molecular weight

The concept is relative.

Its physical meaning

Not at all amazing.

Mass so that the molecules

quickly compare

Need a twelfth

carbon split.

Students rewrite the formula:

m (in-va)

Mr (in-va) = ------------------

1/12 m (C)

You are a molecular

Calculate mass:

atomic masses

Put it all together

And the number of atoms

At the same time, multiply.

The teacher shows the students how to correctly calculate the relative molecular weight of a substance: sodium oxide and sulfuric acid.

4 . Anchoring

Task 1. Divide the following substances into simple and complex: SO 2 K, Cu, N 2, O 2, Cl 2, Al 2 O 3, H 2, Br 2, NaCl, MgSO 4, KOH, Fe, Au, Ag , ZnO, LiI KF, Cr, SO 3

Present the result in the form of a table:

SIMPLE SUBSTANCES	COMPLEX SUBSTANCES

Calculate molecular weights substances (independently with verification).

5. Homework

6. Reflective-evaluative stage

Department of Education Management

Svobodnensky district of the Amur region

MOU Rogachevskaya OOSh

Subject:

"Simple and Complex Substances"

Chemistry Grade 8

Teacher I Categories: Anchukhina T.S.

with. Rogachevka

Target: familiarization with simple and complex substances - the main forms of the existence of elements in nature; performance of tasks for the assimilation of the concepts of "simple substance", "complex substance",Develop skills to distinguish simple substances from complex ones, based on their chemical formulas .

Lesson objectives

educational : 1. to reveal the concepts: simple and complex substances as a form of existence of chemical elements

Developing: 1. To develop cognitive interest in the subject being studied; 2. create conditions for mastering the methods of studying the composition of matter; 3.fto form the ability to search, process, analyze and systematize information; 4. pdevelop the ability to logically express their point of view; 5. teach reflection techniques, develop adequate self-esteem; 6. develop the ability to receive information.

Educational:independently solve problems using existing knowledge; develop the ability to analyze, compare, compare and generalize;learn to be independentin different types of activities;

Planned results.

1. Formation of ideas about the forms of existence of chemical elements in nature and the development of knowledge about chemical elements.

2. Development of students' knowledge about the physical properties of substances.

3. Development of scientific thinking of students in the formation of skills to compare and describe chemical objects in the course of independent performance of exercises and complex tasks, as well as in the development of skills to apply knowledge and methods of action in new conditions.

4. The formation of the scientific worldview of schoolchildren and the assimilation of the leading worldview ideas of the course: the cognizability and unity of the material world, the dependence of the properties of substances on its composition and structure.

5. Development of interest and motivation for studying chemistry when referring to the life experience of schoolchildren and systematizing knowledge about the distribution and relationship of substances in nature.

During the classes:

1. Organizational moment

Hello! Hello dear guests!

Why are you so saddened in chemistry class?

Tell me quickly: in which lesson,

Who dared to offend you in the near past?

So I will be with you today raise the mood,

I know the most The best way:

Let's explore the topic!

2 . Checking homework.

Traditionally again

We start as usual

We check homework.

It's habitual for us.

Get ready to answer

Now I will call!

Scared? I joked…

I will not call!

Better give you tests

I'll give you all grades later.

Exercise 1. In the table, write the letter “X” or “F” (chemical or physical) against each phenomenon, and the letters “T” or “T” against bodies and substances.

"B" respectively .

P/n

Task2. Define the terms "molecule" and "atom".

Task 3. Determine the composition: H 2 O, O 2 , CO 2, Cl 2.

3. Learning new material.

In chemistry, in addition to the terms "atom" and "molecule", the concept of "element" is often used. What is common and how do these concepts differ?A chemical element is an atom of the same kind. So, for example, all hydrogen atoms are the element hydrogen; all oxygen and mercury atoms are the elements oxygen and mercury, respectively.

O 2 , Cl 2. H 2 O, CO 2

How are oxygen and chlorine molecules different from water and carbon dioxide molecules? Students can answer that oxygen and chlorine molecules are formed by atoms of the same type. – Simple substances.Substances water and carbon dioxide are formed by atoms different kind. - Complex substances.

Simple substances - substances formed by atoms of one chemical element.

Ne, Ar, O 2 , Br 2 , I 2 ,O 3 , P 4 , S 8

(Monatomic simple substances are molecules of inert gases; diatomic - molecules of hydrogen, oxygen, chlorine, bromine, iodine; triatomic - ozone, tetraatomic - phosphorus, etc.)

The names of simple substances often coincide with the name of the CE, the atoms of which they are formed.

Simple substances are characterized by certain physical properties (state of aggregation, color, density).

Complex substances (chemical compounds) - These are substances formed by atoms of different chemical elements interconnected.

H 2 O, C 6 H 12 O 6 , NaCl, KMnO 4 , CO 2 , CO

(water, glucose, sodium chloride - table salt, potassium permanganate - potassium permanganate, carbon dioxide, carbon monoxide).

Complex substances are characterized by certain physical properties.

SUBSTANCES

simple complex

H 2 ,O 2 , N 2 , Cl 2 H 2 Oh, CO 2 , H 2 SO 4

Fixing the topic “Simple and complex substances. Relative molecular weight of a substance.

Exercise. Divide the following substances into simple and complex: SO 2 K , Cu , N 2 , O 2 , Cl 2 , Al 2 O 3 , H 2 , Br 2 , NaCl , MgSO 4 , KOH , Fe , Au , Ag , ZnO , LiI KF , Cr , SO 3

Present the result in the form of a table:

SIMPLE SUBSTANCES

Calculate the molecular weights of substances (independently with verification).

Test.

№1

How many simple substances are written in a series of formulas:

H 2 O, N 2, O 3, HNO 3, P 2 O 5, S, Fe, CO 2, KOH.

№2

Both substances are complex:

A) C (coal) and S (sulfur);

B) CO 2 (carbon dioxide) and H 2 O (water);

B) Fe (iron) and CH 4 (methane);

№3

Choose the correct statement:

Simple substances are made up of atoms of the same kind.

A) right

B) False

№4

In what case is it about iron as a chemical element?

A) Iron is a metal that is attracted by a magnet;

B) Iron is part of the composition of rust;

C) Iron has a metallic luster;

D) Iron sulfide contains one iron atom.

№5

In which case is oxygen referred to as simple matter?

A) Oxygen is a gas that supports respiration and combustion;

B) Fish breathe oxygen dissolved in water;

C) The oxygen atom is part of the water molecule;

D) Oxygen is present in the air.

Perform practical tasks in the form of independent work.

Reflection and summing up. What new did you learn in the lesson?What questions caused difficulty?What knowledge have you acquired today?

Homework. §5, 6 p. 25 exercise no. 11–13

Examples practical task:

Instead of dots, insert the necessary expressions (chemical element, simple substance, complex substance, mixture): a) copper oxide ______________, since it consists of _______________________, copper and oxygen; When ____________________ mercury oxide is heated, two ___________________________ are formed: mercury and oxygen.

Fill in the missing words: a) the composition of chemical compounds ___________________ structure _______________________________.

b) substances that are part of mixtures ______________________________ only with the help of _______________________.

c) mechanical mixing _____________________ by the release of heat or other signs chemical reactions.

About atoms and chemical elements

There is nothing else in nature

neither here nor there, in the depths of space:

everything - from small grains of sand to planets -

of the elements consists of a single.

S. P. Shchipachev, "Reading Mendeleev."

In chemistry, apart from terms "atom" and "molecule" concept is often used "element". What is common and how do these concepts differ?

Chemical element – they are atoms of the same type . So, for example, all hydrogen atoms are the element hydrogen; all oxygen and mercury atoms are the elements oxygen and mercury, respectively.

Currently, more than 107 types of atoms, that is, more than 107 chemical elements, are known. It is necessary to distinguish between the concepts of “chemical element”, “atom” and “simple substance”

Simple and complex substances

According to the elemental composition, they are distinguished simple substances, consisting of atoms of one element (H 2, O 2, Cl 2, P 4, Na, Cu, Au), and complex substances, consisting of atoms of different elements (H 2 O, NH 3, OF 2, H 2 SO 4, MgCl 2, K 2 SO 4).

Currently, 115 chemical elements are known, which form about 500 simple substances.

Native gold is a simple substance.

The ability of one element to exist in the form of various simple substances that differ in properties is called allotropy.For example, the element oxygen O has two allotropic forms - dioxygen O 2 and ozone O 3 with a different number of atoms in molecules.

The allotropic forms of the element carbon C - diamond and graphite - differ in the structure of their crystals. There are other reasons for allotropy.

chemical compounds, for example, mercury (II) oxide HgO (obtained by combining atoms of simple substances - mercury Hg and oxygen O 2), sodium bromide (obtained by combining atoms of simple substances - sodium Na and bromine Br 2).

So let's summarize the above. Molecules of matter are of two types:

1. Simple Molecules of such substances consist of atoms of the same type. In chemical reactions, they cannot decompose with the formation of several simpler substances.

2. Complex- Molecules of such substances consist of atoms of different types. In chemical reactions, they can decompose to form simpler substances.

The difference between the concepts of "chemical element" and "simple substance"

Distinguish concepts "chemical element" and "simple substance" when comparing the properties of simple and complex substances. For example, a simple substance oxygen- a colorless gas necessary for breathing, supporting combustion. The smallest particle of a simple substance oxygen is a molecule that consists of two atoms. Oxygen is also included in the composition of carbon monoxide (carbon monoxide) and water. However, the composition of water and carbon monoxide includes chemically bound oxygen, which does not have the properties of a simple substance, in particular, it cannot be used for breathing. Fish, for example, do not breathe chemically bound oxygen, which is part of the water molecule, but free, dissolved in it. That's why when we are talking about the composition of any chemical compounds, it should be understood that these compounds do not include simple substances, but atoms of a certain type, that is, the corresponding elements.

When complex substances are decomposed, atoms can be released in a free state and combined to form simple substances. Simple substances are made up of atoms of one element. The difference between the concepts of "chemical element" and "simple substance" is also confirmed by the fact that one and the same element can form several simple substances. For example, atoms of the element oxygen can form diatomic oxygen molecules and triatomic ozone molecules. Oxygen and ozone are completely different simple substances. This explains the fact that much more simple substances are known than chemical elements.

Using the concept of "chemical element", we can give the following definition of simple and complex substances:

Simple substances are substances that consist of atoms of one chemical element.

Substances that are composed of atoms of different chemical elements are called complex.

The difference between the concepts of "mixture" and "chemical compound"

Compounds are often called chemical compounds.

Try to answer the questions:

1. What is the difference in the composition of the mixture from chemical compounds?

2. Compare the properties of mixtures and chemical compounds?

3. In what ways can a mixture and a chemical compound be divided into constituent components?

4. Is it possible to judge outward signs about the formation of a mixture and chemical compound?

Comparative characteristics of mixtures and chemical

Questions for comparing mixtures with chemical compounds	Mapping
Questions for comparing mixtures with chemical compounds	Mixes	Chemical compounds
How do mixtures differ from chemical compounds in composition?	Substances can be mixed in any ratio, i.e. the composition of mixtures is variable	The composition of chemical compounds is constant.
Compare the properties of mixtures and chemical compounds?	Substances in mixtures retain their properties	Substances that form compounds do not retain their properties, since chemical compounds with different properties are formed.
How can a mixture and a chemical compound be separated into its constituent components?	Substances can be divided by physical means	Chemical compounds can only be decomposed by chemical reactions
Is it possible to judge by external signs the formation of a mixture and a chemical compound?	Mechanical mixing is not accompanied by heat release or other signs of chemical reactions	The formation of a chemical compound can be judged by signs of chemical reactions

Tasks for fixing

I. Work with the machines

II. Solve the task

From the proposed list of substances, write out separately simple and complex substances:
NaCl, H 2 SO 4 , K, S 8 , CO 2 , O 3 , H 3 PO 4 , N 2 , Fe.
Explain your choice, in each case.

III. Answer the questions

№1

How many simple substances are written in a series of formulas:
H 2 O, N 2, O 3, HNO 3, P 2 O 5, S, Fe, CO 2, KOH.

№2

Both substances are complex:

A) C (coal) and S (sulfur);
B) CO 2 (carbon dioxide) and H 2 O (water);
B) Fe (iron) and CH 4 (methane);
D) H 2 SO 4 (sulfuric acid) and H 2 (hydrogen).

№3

Choose the correct statement:
Simple substances are made up of atoms of the same kind.

A) right

B) False

№4

Mixtures are characterized by
A) they have a constant composition;
B) Substances in the "mixture" do not retain their individual properties;
C) Substances in "mixtures" can be separated by physical properties;
D) Substances in "mixtures" can be separated by a chemical reaction.

№5

For "chemical compounds" the following is typical:
A) Variable composition;
B) Substances in the composition of a "chemical compound" can be separated by physical means;
C) The formation of a chemical compound can be judged by the signs of chemical reactions;
D) permanent composition.

№6

In what case is it about gland how about chemical element?
A) Iron is a metal that is attracted by a magnet;
B) Iron is part of the composition of rust;
C) Iron has a metallic luster;
D) Iron sulfide contains one iron atom.

№7

In what case is it about oxygen as a simple substance?
A) Oxygen is a gas that supports respiration and combustion;
B) Fish breathe oxygen dissolved in water;
C) The oxygen atom is part of the water molecule;
D) Oxygen is present in the air.

lesson project

Lesson project for learning new material on the topic "Simple and Complex Substances" (lesson number 2)

Grade 8

WMC“Chemistry grade 8. Gabrielyan O.S. 2014"

Class composition: there are 28 people in the class, 27 of them with a developmental norm, 1 with a mental retardation (1 type)

Lesson Objectives: CREATE CONDITIONS FOR

"ordinary" children

"special" children

Discovery of a way to find differences between a simple substance and a complex one, a pure substance and a mixture, a chemical element and a simple substance;

formation of the ability to distinguish simple substances from complex ones, based on their chemical formulas

developing the ability to identifythe main thing is to compare, analyze, draw conclusions.

To develop the ability to provide assistance in the position of a "little teacher"

Acceptance and understandingwayaction forfinding differences between a simple substance and a complex one, a pure substance and a mixture, a chemical element and a simple substance, based on their chemical formulas

To develop the ability to negotiate when working in pairs

PLANNED RESULTS

Personal : showing interest in the problem
Metasubject

Interact in pairs

- ability to work on the development of an algorithmfinding differences between a simple substance and a complex one, a pure substance and a mixture, a chemical element and a simple substance

subject

Personal : showing interest in the problem

Metasubject

Use sign-symbolic models

Interact in pairs

Plan actions in accordance with the set educational task;

- algorithmic skills finding difference between a simple substance and a complex

Exercise self-control and self-assessment.

subject : identify simple substances and complex ones, pure substances and mixtures, chemical elements and simple substances

Lesson content

Lesson structure

Interaction in educational process

Note

Actions of the teacher

Student actions

with the norm of development

Student actions

with disabilities

Motivation

Are you all ready for the lesson to learn about something new?

Refers to the class:

Look at the formulas of the substances written on the board.

– What do they mean?

How are they similar, how are they different?

Yes that's right!

In the first column, substances consisting of atoms of the same type, and in the second - from atoms of different types

In the first column of matter, easier written, few atoms

I organize a situation of control and self-assessment of readiness for the upcoming work in the lesson.

Simple and complex substances are written on the board in two columns.

H2H2O

O 2 K 2 O

N 2 NH 3

S H 2 SO 4

2. goal setting

Try to formulate the topic of the lesson.

The theme of the lesson will be:

"Simple and Complex Substances"

- Who can repeat the purpose of the lesson?

Talk to each other in pairs, and the "little teachers" will check you

Working in pairs, complete the sentence “Today I will study at the lesson ....”

Formulate the topic of the lesson

Recorded in a notebook

"Little teachers" check the correct pronunciation of the topic

Work in pairs to determine the purpose of the lesson.

Repeat the theme of the lesson

Recorded in a notebook

They speak to each other.

Work in pairs, pronounce the goal

- “Today I will study at the lesson identify simple and complex substances

I ask the "special child" in the class, I praise.

An opportunity is given to respond to a “special” child.

Fixing the topic on the board.

3. Planning

To easily learn to distinguish between simple and complex substances, we need a plan that includes questions:

-What?

-How?

-I apply

- Scale of success.

Refers to a group of "special children":

You have cut strips on the tables with certain items that need to be distributed in the desired sequence

Work in pairs to create a plan that includes the following questions:

-What?

-How?

-I apply

- Scale of success.

Arrange plan items in order

Fixing the plan on the board:

4. Implementation learning task

-What do we do at step 1 of the plan?

Whatcan you tell me about simple substances

Whatcan you tell me about complex substances

How to distinguish between simple and complex substances?

From the row written on the board, choose only simple substances. Check if your neighbor did the right thing in a pair.

How many complex substances are in this series? Write down a substance consisting of 4 atoms, of which 3 belong to the same species.

Refers to a group of "special children":

Look carefully at the formulas of complex substances, count how many atoms of different types are in each molecule

Write a formula for a substance that has two iron atoms and three oxygen atoms. What is this substance?

Test each other in pairs

They tell what they learned about simple substances, give an example. Formulate and write down the definition

Tell what they learned about complex substances, give an example

Formulate and write down the definition

Compose and write an algorithm

Issued, checked

Answer:

3 complex substances

MgO , PH 3 , HNO 3

Discharge PH 3

Compose, check, determine the type of substance.

Checking

Write down the definition and example

Write down the algorithm

Issued, checked

Answer:

3 complex substances

They count the number of atoms of different types in each molecule, find a molecule with four atoms, determine that 3 of them belong to the same species.

Discharge PH 3

Write down the signs of chemical elements, put the number of atoms. They try to determine the type of substance using hint cards.

Checking

The “special” child is given the opportunity to repeat what he wrote in his notebook, which he gave an example.

There are a number of substances on the board:

F 2 , Cu, MgO, PH 3 , HNO 3 , C

Highlight complex substances on the board

We check verbally

Separately check in special children, fixing whether there are difficulties

Topic: Simple and complex substances. Chemical element.

About atoms and chemical elements

There is nothing else in nature

neither here nor there, in the depths of space:

everything - from small grains of sand to planets -

of the elements consists of a single.

S. P. Shchipachev, "Reading Mendeleev."

In chemistry, in addition to the terms "atom" and "molecule", the concept of "element" is often used. What is common and how do these concepts differ?

Chemical elementare atoms of the same type.So, for example, all hydrogen atoms are the element hydrogen; all oxygen and mercury atoms are the elements oxygen and mercury, respectively.

Simple and complex substances

By elemental composition, simple substances are distinguished, consisting of atoms of one element (H2, O2, Cl2, P4, Na, Cu, Au), and complex substances, consisting of atoms of different elements (H2O, NH3, OF2, H2SO4, MgCl2, K2SO4) .

Currently, 115 chemical elements are known, which form about 500 simple substances.

Native gold is a simple substance.

The ability of one element to exist in the form of various simple substances that differ in properties is called allotropy. For example, the element oxygen O has two allotropic forms - dioxygen O2 and ozone O3 with a different number of atoms in the molecules.

The allotropic forms of the element carbon C - diamond and graphite - differ in the structure of their crystals. There are other reasons for allotropy.

Element name

Allotropic forms

Carbon C

Graphite

Diamond

Complex substances are often called chemical compounds, for example, mercury (II) oxide HgO (obtained by combining atoms of simple substances - mercury Hg and oxygen O2), sodium bromide (obtained by combining atoms of simple substances - sodium Na and bromine Br2).

So let's summarize the above. Molecules of matter are of two types:

1. Simple - the molecules of such substances consist of atoms of the same type. In chemical reactions, they cannot decompose with the formation of several simpler substances.

2. Complex - the molecules of such substances consist of atoms of different types. In chemical reactions, they can decompose to form simpler substances.

The difference between the concepts of "chemical element" and "simple substance"

The concepts of “chemical element” and “simple substance” can be distinguished by comparing the properties of simple and complex substances. For example, a simple substance - oxygen - a colorless gas necessary for breathing, supporting combustion. The smallest particle of a simple substance oxygen is a molecule that consists of two atoms. Oxygen is also included in the composition of carbon monoxide (carbon monoxide) and water. However, the composition of water and carbon monoxide includes chemically bound oxygen, which does not have the properties of a simple substance, in particular, it cannot be used for breathing. Fish, for example, do not breathe chemically bound oxygen, which is part of the water molecule, but free, dissolved in it. Therefore, when it comes to the composition of any chemical compounds, it should be understood that these compounds do not include simple substances, but atoms of a certain type, that is, the corresponding elements.

Using the concept of "chemical element", we can give the following definition of simple and complex substances:

Simple substances are substances that consist of atoms of one chemical element.

Substances that are composed of atoms of different chemical elements are called complex.

The difference between the concepts of "mixture" and "chemical compound"

Complex substances are often called chemical compounds.

Try to answer the questions:

1. What is the difference in the composition of the mixture from chemical compounds?

2. Compare the properties of mixtures and chemical compounds?

3. In what ways can a mixture and a chemical compound be divided into constituent components?

Comparative characteristics of mixtures and chemical

Questions for comparing mixtures with chemical compounds

Mapping

Mixes

Chemical compounds

How do mixtures differ from chemical compounds in composition?

Substances can be mixed in any ratio, i.e. the composition of mixtures is variable

The composition of chemical compounds is constant.

Compare the properties of mixtures and chemical compounds?

Substances in mixtures retain their properties

Substances that form compounds do not retain their properties, since chemical compounds with different properties are formed.

How can a mixture and a chemical compound be separated into its constituent components?

Substances can be separated by physical means

Chemical compounds can only be decomposed by chemical reactions

Is it possible to judge by external signs the formation of a mixture and a chemical compound?

Mechanical mixing is not accompanied by the release of heat or other signs of chemical reactions

The formation of a chemical compound can be judged by signs of chemical reactions

II. Solve the task

From the proposed list of substances, write out separately simple and complex substances:
NaCl, H2SO4, K, S8, CO2, O3, H3PO4, N2, Fe.
Explain your choice, in each case.

III. Answer the questions

№1

How many simple substances are written in a series of formulas:
H2O, N2, O3, HNO3, P2O5, S, Fe, CO2, KOH.

№2

Both substances are complex:

A) C (coal) and S (sulfur);
B) CO2 (carbon dioxide) and H2O (water);
C) Fe (iron) and CH4 (methane);
D) H2SO4 (sulfuric acid) and H2 (hydrogen).

№3

Choose the correct statement:
Simple substances are made up of atoms of the same kind.

A) right

B) False

№4

№5

№6

In what case is it about iron as a chemical element?
A) Iron is a metal that is attracted by a magnet;
B) Iron is part of the composition of rust;
C) Iron has a metallic luster;
D) Iron sulfide contains one iron atom.

№7

If you reply with a "+" sign, users are added to the message and an email notification is sent to them.

Checking access settings...

Add

Cancel

You do not have permission to add comments.