- •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
- •Words to be remembered:
- •Notes on the text:
- •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:
diamond flame
soft odour
lubricant solubility thoroughly blood to burn tissue deficiency fuel
Notes on the texts:
charcoal – древесный уголь amorphous – аморфный, некристаллический
allotropic – аллотропный because of – из-за
№17
Carbon dioxide
Carbon dioxide is a colourless, odourless gas with a weakly acid taste, due to the formation of some carbonic acid when it is dissolved in water. It appears to be about 50% heavier than air. It is easily soluble in water, one liter of water at 0°C dissolving 1,713 ml of gas under 1 atm pressure.
When crystalline carbon dioxide is heated from a very low temperature its vapour pressure reaches 1 atm at 79° at which temperature it vaporizes without melting. If pressure were increased to 2,5 atm the crystalline substance could be changed directly to a gas.
Carbon dioxide is known to combine with water to form carbonic acid H2CO3, it being a weak acid.
If you studied all the properties more thoroughly you would see that carbon dioxide is used for the manufacture of sodium carbonate, sodium hydrogen carbonate, and carbonated water and for many other uses.
From this short review It's clear that chemistry of carbon and its compounds is a very Important Held of chemistry and should be studied carefully.
Words to be remembered:
colourless to vaporize
odourless to increase
acid to combine
taste weak
due to sodium
to dissolve review
soluable carefully
№18
FUEL
Carbon and hydrogen are the principal constituents of the solid fuels coal and wood. Coal has been formed in nature by the slow decomposition of vegetable matter, in the presence of water and absence of air. Most of it was formed during the Carbonifereous Period of geologic time, about 250 million years ago. Coal consists of free carbon mixed with various carbon сom
pounds and some mineral matter. Anthracite coal (hard coal) contains much volatile matter, and burns with a smoky flame.
Bituminous coal can be converted into coke by heating without access of air. When the heating lit carried out in a by-product coke oven, many substances distill out, including gas for fuel, ammonia and a complex mixture of liquid and solid organic compounds. The solid material remaining in the ovens, consisting mainly of carbon, is called coke. It burns with a nearly colorless flame, and is used in great amounts in metallurgical processes.
Petroleum is a very important liquid fuel. It is a complex mixture of compounds of carbon and hydrogen.
The gas obtained from a coke furnace (coal gas) consists of hydrogen (about 50%), methane CH4(30%), carbon monoxide (10%) and minor components. This coal gas was the original illuminating gas.
Natural gas, from gas wells and all wells, consists largely of methane.