Презентация на тему по английскому языку Химия вокруг нас

elementary match to a beautiful blue sky above your

head, you can also consider from another point of view - from the point of view of the remarkable science of chemistry. Yes, yes, the objects with which we are surrounded, which we see every day, without thinking about what they are, can be very surprising and unusual for a chemist.

glass goes back to antiquity. It is known that

in Egypt and Mesopotamia he was able to do it already 6000 years ago. Probably, glass was started to be manufactured later than the first ceramic products, because higher temperatures were required for its production than for clay burning. If only clay is sufficient for the simplest ceramic products, then at least three components are required in the glass composition.

used in glassware, in which the total amount of

contaminants does not exceed 2-3%. Particularly undesirable is the presence of iron, which even in minute amounts (tenths of%) stains the glass in a greenish color. If soda Na2CO3 is added to the sand, it is possible to weld the glass at a lower temperature (200-300 ° C). Such a melt will have less viscous (bubbles are easier to remove during cooking, and products are easier to form). But! Such glass is soluble in water, and products from it are subject to destruction under the influence of atmospheric influences. To impart insolubility to the glass in water, a third component is introduced into it: lime, limestone, chalk. All of them are characterized by the same chemical formula - CaCO3.

SO ON...

CARBOHYDRATES

reinforced concrete,

brick, paint, asbestos. roofing material.
drying oil,

var,
refractory impregnation, nails,
instruments...

that in a living organism not only all chemical

elements are present, but each of them performs a certain biological function. Reliably established the role of about 30 chemical elements, without which the human body can not normally exist. These elements are called vital.
The human body consists of 60% water, 34% organic and 6% inorganic substances. The main components of organic substances are carbon, hydrogen and oxygen, they also include nitrogen, phosphorus and sulfur. In the inorganic substances of man there are necessarily 22 chemical elements: Ca, P, O, Na, Mg, S, B, Cl, K, V, Mn, Fe, Co, Ni, Cu, Zn, Mo, Cr, Si, I, F, Se. Scientists agreed that if the mass fraction of the element in the body exceeds 10-2%, then it should be considered a macro element. The proportion of microelements in the human body is 10-3 - 10-5%. If the content of the element is below 10-5%, it is considered an ultramicroelement.

divided into artificial and synthetic fibers. Artificial fibers are

made from natural high-molecular compounds, mainly from cellulose. Synthetic fibers are made from synthetic high-molecular compounds.

Chemical fibers are made in the form of an endless filament consisting of many individual fibers or of a single fiber, or in the form of a staple fiber - short lengths (staples) of untwisted fiber, the length of which corresponds to the length of the fiber of wool or cotton. Staple fiber, like wool or cotton, serves as a semi-product for yarn production. Before spinning, the staple fiber can be mixed with wool or cotton.

acetate silk

e s

metals

alloys

polimers

semiconductors

was known to man before the new era of

chronology. Scientists do not have information about the beginning of cooking soap in the Arab countries and China. The earliest written mention of soap in European countries is found in the Roman writer and scientist Pliny the Elder (23-79 gg.). In the treatise "Natural History" (in 37 volumes), which, in essence, was an encyclopedia of natural science knowledge of antiquity, Pliny wrote about the ways of cooking soap with saponification of fats. Moreover, he wrote about a hard and soft soap, obtained using soda and potash, respectively. Previously, for washing clothes used lye, obtained from the treatment of ash water. Most likely it was before it became known that the ash from the burning of fuel of vegetable origin contains potash.

kerosene
F u e l o i l

diesel oil

varnishes and paints

electric lamp
The light

bulb consists of a glass bottle into which the spiral holders are inserted, and from the spiral itself. The spiral is made of tungsten - one of the most refractory metals. Its melting point is 3410 ° C. In addition to high refractoriness, tungsten has another very important property - high plasticity. From 1 kg. tungsten can pull the wire length of 3.5 km, which is enough to manufacture 23 thousand 60-watt light bulbs. The holder is made of molybdenum, an analogue element of tungsten. In the periodic table of DI Mendeleyev, these two elements are in the same subgroup. The most important property of molybdenum is the small coefficient of linear expansion. When heated, it increases in size in the same way as glass. Since molybdenum and glass change their sizes synchronously with heating and cooling, the latter does not crack and therefore the sealing does not fail.

rises, the composition of particles that can exist in

the atmosphere of the star becomes simpler. Spectral analysis of stars of the classes O, B, A (temperature from 50 000 to 100 000 C) shows in their atmospheres lines of ionized hydrogen and helium and metal ions, in the class K (5000 C) radicals are already detected, and in class M (3800 C ) - even oxides molecules.