Chemical reactions are the interaction of substances accompanied with change of their structure. In other words, the substances reacting do not correspond to the substances which are turning out as a result of reaction. Faces similar interactions of people hourly, every minute. The processes proceeding in its organism (breath, synthesis of proteins, digestion, etc.) are chemical reactions too.
Instruction
1. Any chemical reaction has to be written down correctly. One of the main requirements - that amount of atoms of each element of the substances which are in the left part of reaction (they are called by "initial substances"), corresponded to amount of atoms of the same element in substances of the right part (they are called – "reaction products"). In other words, record of reaction has to be balanced.
2. Let's review a concrete example. What occurs when in kitchen light a gas ring? Natural gas reacts with air oxygen. This reaction of oxidation so exothermic, that is accompanied with allocation of heat that there is a flame. By means of which you either cook food, or warm already prepared.
3. For simplification assume that natural gas consists only of one its component – the methane having CH4 formula. As to make and balance this reaction?
4. At combustion of carbon-containing fuel, that is at carbon oxidation, oxygen forms carbon dioxide. Its formula is known to you: CO2. And what is formed at oxidation of the hydrogen which is contained in methane by oxygen? Naturally, water in the form of steam. Its formula is known by heart even by the person, farthest from chemistry: H2O.
5. So, write down initial substances in the left part of reaction: CH4 + O2. In right, respectively, there will be reaction products: CO2 + H2O.
6. Preliminary record of this chemical reaction will be following: CH4 + O2 = CO2 + H2O.
7. Balance the above-written reaction, that is achieve implementation of the basic rule: the amount of atoms of each element in the left and right parts of chemical reaction has to be identical.
8. You see that the amount of atoms of carbon coincides, and amount of atoms of oxygen and hydrogen a miscellaneous. In the left part 4 atoms of hydrogen, and in right - only 2. Therefore deliver before a water formula coefficient 2. Receive: CH4 + O2 = CO2 + 2H2O.
9. Atoms of carbon and hydrogen are balanced, now it was necessary to make the same with oxygen. In the left part of atoms of oxygen 2, and in right – 4. Having delivered coefficient 2 before an oxygen molecule, receive final record of reaction of oxidation of methane: CH4 + 2O2 = CO2 + 2H2O.