Presentation for the lesson Pure substances and mixtures presentation for a chemistry lesson (grade 8) on the topic. Chemistry presentation on the topic "Pure substances and mixtures
Lesson Objectives:
To find out:
- What substance is considered pure?
- What is a mixture?
- What are the mixtures?
- How can a mixture be separated?
Definition of "mixture"
was given in the 17th century. English scientist Robert Boyle:
"A mixture is an integral system consisting of heterogeneous components."
Comparative characteristics pure substance and mixture
Signs of comparison
pure substance
Compound
Mixture
Constant
Substances
Same
fickle
Physical Properties
Energy change during formation
Various
Permanent
going on
Fickle
Separation
Not happening
Through chemical reactions
Physical methods
- They call it clean substances that have constant composition and constant physical properties.
Mixture is a combination of different substances.
- Milk
- metal alloys
- Solutions
- Fog
- Concrete
- and others
distinctive feature of mixtures
In mixtures, each of their constituent substances retains its individual properties.
These are mixtures in which particles of substances are visible to the naked eye.
these are mixtures in which particles of substances cannot be seen.
Homogeneous
Heterogeneous
suspensions
liquid
emulsions
gaseous
solid
Test your knowledge From the proposed substances, name the pure ones:
- Water in the river
- water in the cloud
- Sugar
- Petrol
- Salt
Test your knowledge
1. A mixture is:
A. Distilled water
C. Aluminum
2. A mixture is not:
- Distilled water
- The soil
Test your knowledge
3. Specify inhomogeneous mixtures
A) granulated sugar + water
B) sulfur + iron filings
B) salt + water
Test your knowledge
4. Specify homogeneous mixtures
B) river sand + water
B) oil + water
Test your knowledge
5. In what case is it about water as a pure substance?
A) sea water tastes salty
B) distilled water is obtained by cooling water vapor
C) mineral water is used to treat certain diseases
Test your knowledge
6. Mark the mixture in which the main component is gas
A) oxygen
B) carbon dioxide
Explain from a chemical point of view:
“Meanwhile, the Needlewoman returns, strains the water, pours it into jugs; and what an entertainer: if the water is unclean, then she folds a sheet of paper, puts coals in it and pours coarse sand, inserts that paper into a jug and pours water into it, but you know the water passes through the sand and through the coals and drops into the jug clean like crystal…”
(Odoevsky V.F. "Moroz Ivanovich")
§ 24, ex. 4,5,6,7
Creative task.
1. Make tasks for the separation of the mixture.
2. You were given a mixture of salt and chalk. Suggest ways to separate this mixture.
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Slides captions:
PURE SUBSTANCES MIXTURES
WORK PLAN Substance characteristics: according to different types of classification; 2. The concept of "pure substance" and "mixture": a description of the concepts; qualification of pure substances; classification of mixtures; 3. Experimental work. Conclusions.
Characteristics of the substance BY COMPOSITION BY AGGREGATE STATE BY PHYSICAL PROPERTIES
Differences in the properties of substances Resource on the Internet http://www.alhimik.ru/teleclass/tests/test003.htm
PURE SUBSTANCES MIXTURES
PURE SUBSTANCE MIXTURE
PURE SUBSTANCE A MIXTURE CONSISTS OF THE SAME PARTICLES (ATOMS, MOLECULES, IONS)
PURE SUBSTANCE A MIXTURE CONSISTS OF THE SAME PARTICLES (ATOMS, MOLECULES, IONS) CONSISTS OF SEVERAL DIFFERENT SUBSTANCES
According to the regulations existing in Russia, the following qualifications have been established for reagents: pure (pure) pure for analysis (analytically pure) chemically pure (chemically pure) extra pure (high purity)
EXPERIMENT Safety rules! TASK: 1) MIXTURE PREPARATION; 2) INVESTIGATION OF MIXTURE PROPERTIES.
MIXTURES OF HOMO - GENE (uniformly related) HETEROGENEOUS (heterogeneous)
oxygen O 2 hydrogen H 2 water H 2 O pure, simple substances complex substance mixture: homogeneous; heterogeneous
WHAT SUBSTANCE IS WE TALKING ABOUT? In living cells and depths, Life provides hemoglobin. Courageous metal he is, But in the side group himself. And especially personal pride - Steel is excellent from it! Fe
WHAT SUBSTANCE IS WE TALKING ABOUT? Yellow, sunny, beautiful non-metal. How famous! Hundreds of years he lives in the world, In medicine applicable. With hydrogen, it's terrible, Poisonous and ... oh, dangerous! All living beings Die twice two. S
EXPERIMENT Substances: IRON - Fe SULFUR - S TASK: CHARACTERISTICS OF PHYSICAL PROPERTIES OF SUBSTANCES; 2) MIXTURE PREPARATION; 3) INVESTIGATION OF MIXTURE PROPERTIES.
Comparative characteristics of a mixture and a pure substance Signs of comparison Pure substance Mixture Composition of a substance Physical properties Separation
Comparative characteristics of a mixture and a pure substance Signs of comparison Pure substance Mixture Composition Constant Variable (variable) Substances Physical properties Separation
Comparative characteristics of a mixture and a pure substance Signs of comparison Pure substance Mixture Composition Constant Variable (variable) Substances Same Different Physical properties Separation
Comparative characteristics of a mixture and a pure substance Signs of comparison Pure substance Mixture Composition Constant Inconstant (variable) Substances The same Different Physical properties Constant Inconstant Separation
Comparative characteristics of a mixture and a pure substance Signs of comparison Pure substance Mixture Composition Permanent Variable (variable) Substances The same Various Physical properties Constant Variable Separation Using chemical reactions Physical methods
Comparative characteristics of a mixture and a pure substance Signs of comparison Pure substance Mixture Composition Permanent Variable (variable) Substances The same Various Physical properties Constant Variable Separation Using chemical reactions Physical methods
Lesson results 1. Concepts: "pure substance" qualification of pure substances; "mixture" classification of mixtures; 2. We studied the properties of substances in a mixture
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Slides captions:
Pure substances and mixtures. Physical phenomena in chemistry.
Pure substances are substances that have constant physical properties.
A mixture is a combination of different substances that can be separated because they have different physical properties (eg different boiling points). Substances in a mixture are not bound by chemical bonds, so they can be separated from each other.
Mixtures Homogeneous (homogeneous) Heterogeneous (heterogeneous) Solutions of table salt (sodium chloride) and sugar in water, air Mixture of table salt with sand, clay with water, iron filings with clay
Problem: How to get pure substances?
The basis for obtaining pure substances was physical processes that occur without changing the composition of the substance, but with a change in the aggregate states of substances.
Heterogeneous mixtures Settling Filtration Magnet action Settling clay particles in water. Used for cleaning drinking water Used in drinking water purification Separation of iron from other substances
Homogeneous mixtures Evaporation Crystallization Distillation (distillation) Chromatography Isolation of common salt from sea water Sugar production Obtaining distilled water Separation and purification of medicinal substances
How to purify water while hiking?
Mixtures are given: - iron and copper filings; - sawdust and clay; - river sand and sugar. Suggest ways to separate them.
On the topic: methodological developments, presentations and notes
Lesson summary "Pure substances and mixtures. Methods for separating mixtures"
Lesson objectives: 1. Educational: Give the concept of a pure substance and a mixture of substances, the similarities and differences between them. To reveal the meaning of mixtures in nature and human life.2. Educational: F...