- •Chemistry
- •Introduction
- •Some facts about chemistry
- •Some facts about atoms (I)
- •Some facts about atoms (II)
- •The atomic model
- •The nature of ceramics
- •Construction materials
- •The measurements in chemistry
- •The metric system
- •Isotopes
- •Liquids (I)
- •Words to be remembered:
- •Liquids (II)
- •Words to be remembered:
- •Solid state (I)
- •Words to be remembered:
- •Solid state (II)
- •Words to be remembered:
- •Properties of solids
- •Notes on the texts:
- •Words to be remembered:
- •Organic chemistry
- •Word to be remembered:
- •Elementary carbon
- •Words to be remembered:
- •Notes on the texts:
- •Carbon dioxide
- •Words to be remembered:
- •Words to be remembered:
- •Hydrogen
- •Words to be remembered):
Words to be remembered:
to consider copper
electric current considerable
discovery effort
to arrange to appear
for instance to solve
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Properties of solids
The molecules of solids are close to each other, they are vibrating in a fixed position. There is a strong force of attraction between molecules in a solid. Because of the strong attraction between molecules solids have certain properties. If we examined solids thoroughly, we should find that these properties are: tenacity, hardness, malleability and ductility.
Tenacity is a measure of solid’s resistance to being pulled apart. Steel has a high tensile strengths concrete has a much lower tensile strength. Hardness is a measure of a substance’s ability to scratch another substance. The diamond is the hardest solid, it being able to scratch all other substances.
Malleability refers to a solid’s ability to be hammered or rolled into thin sheets. Gold is famous for its malleability, copper, tin and aluminum being other examples of malleable materials.
Ductility is the ability to be drawn out in the form of wires.
Notes on the texts:
tenacity - вязкость to scratch - царапать
malleability - ковкость to draw our - извлекать
ductility - пластичности wire - провод
Words to be remembered:
attraction tensile
certain concrete
hardness strength
resistance ability
tensile diamond
№15
Organic chemistry
Organic chemistry is an extremely interesting field of natural science and of great technological significance. The overwhelming majority of chemists prove to be engaged in producing organic compounds, several millions being known so far.
In view of their obvious success in the manufacture of synthetic compounds, the chemists are greatly interested in this field of science.
The name organic chemistry, which was originally used to refer to the chemistry of substances that occur in living organisms, is now used for the chemistry of the compounds of carbon. The chemistry of carbon was greatly influenced about a century age through the development of a general structure theory, this theory being a chemical theory, induced from chemical facts.
In recent years it has received added verification through the determination of exact structures of molecules and crystals by physical methods, especially X-ray diffraction, electron diffraction, and the analysis of the spectra of substances.
During the first half of the 19th century many organic compounds were found, to have been obtained from plants and animals and also to have been made in the laboratory. They were analyzed for their constituent elements and their properties were carefully studied. Efforts were made to find some correlation between the chemical composition and the properties of the substances.