How to write chemical equations faster

Chemical formulas and reactions

Symbols and formulas

Chemical elements have been known since ancient times. Metals were extracted from ores and alchemists were already experimenting with sulfur and mercury. However, one was missing Order and uniform designation of the elements and their connections. Knowledge sharing was very difficult.

For this reason, uniform names and Chemical elements icons set. Today we can do this Periodic table of the elements remove. But it was a long way to develop this instrument.

Berzelius made a great contribution to communication among researchers. He led the chemical sign language a. This allowed the elements to be abbreviated, which saved a lot of time, and everyone understood the meaning of these symbols. For example, got oxygen the symbol O and hydrogen was abbreviated with H.

From the chemical symbols it was now possible to put together compounds of the elements. For this you need knowledge of the Valencies and Oxidation numbers. Oxygen in compounds almost always has an oxidation number of -2. Alkali metals (1 main group) have the oxidation number +1 in compounds. One can now use the formula for the electrically neutral Alkali metal oxides put up.

Ox. O: -2

Ox. K: +1

$ K_2O $

At the Preparation of chemical formulas and complete Reaction equations Fixed rules and laws like the law of the constant proportions.

Chemical reaction

Chemical reaction run constantly around us every day and also within us. So we breathe oxygen in and carbon dioxide out again. Photosynthesis takes place in plants, the basis of autotrophic and heterotrophic dietin which they convert the carbon dioxide into oxygen and sugar. When you light a candle, you have started a chemical reaction.

From these examples you can already see a characteristic of chemical reactions: the Substance conversion.

Using the example of the reaction of Iron with sulfur it becomes clear. The starting materials (starting materials) are iron and sulfur. After the reaction, a black powder remains: that Iron sulfide. The sulphide is neither shiny metallic like iron nor yellow like sulfur. So a new material was created with new properties. This reaction can be seen in a Establish reaction equation and represent.

$ Fe + S \ longrightarrow ~ FeS $

Energy turnover

Another characteristic of a chemical reaction is that Energy turnover. If new Ties be knotted so that new fabrics are created, either energy free or energy is absorbed.

Are the educts more energetic than the products, one speaks of one exothermic reaction. Energy is released in the form of heat and / or light. We use this for heating, for example.

The opposite is the case endothermic reaction. Here the starting materials have less energy than the products. In the course of the reaction, energy is absorbed from the environment. This is an example of this Dissolving table salt in water.

So in chemical reactions there is one Energy conversion. The energy is not lost, it only changes that Manifestation. Chemical energy is converted into heat and light energy. In case of a battery chemical energy is converted into electrical energy. In any case, the Conservation of energy law.

Conservation of mass law

Just like the energy, the mass is also retained in a chemical reaction. this will Conservation of mass law called. So mass can neither be created nor destroyed. In relation to a chemical reaction, this means: There are the same number of atoms of the same type before and after the reaction. Just that Binding relationships vary. The atoms are thus linked in a different way, but are still present in the products. That is why it is important to have a Correctly balance the reaction equation to be able to.

Let us take the example of the reaction of aluminum and oxygen Alumina:

$ Al + O_2 \ longrightarrow ~ Al_2O_3 $.

If you count the individual atoms, you will find that there are not the same number on both sides. So it has to be balanced. There are 3 atoms of oxygen in aluminum oxide. There are 2 atoms of oxygen in the oxygen molecule. The least common multiple is 6. A 3 is written in front of oxygen and a 2 in front of the aluminum oxide. Now aluminum has to be compensated. There are now 4 aluminum atoms on the product side. Therefore 4 aluminum atoms are required on the educt side. The following equation results:

$ 4 ~ Al + 3 ~ O_2 \ longrightarrow ~ 2 ~ Al_2O_3 $.