Chemical Reactions

Chemical reactions is one of the topics that people usually think about when they hear chemistry. They are related to explosions, burning and many other exciting processes.

Chemical reactions differ from the chemical procedures which lead to mixtures, since the reactions either result into compounds by fusing a compound with one or more element or two elements with each other into a new substance, which is also a compound. It also works in the other way, so chemical reactions also split compounds. This article will give you a lot of information regarding the chemical reactions.

How do chemical reactions work?

Chemical reactions are actually easy to explain. Basically, one or more substances, the reactants, react and form products. The atoms of the reactants rearrange into new formations, which means there is now a new substance. This happens if the two reactants receive an amount of energy.

Only a given amount of the one reactant does react with also an amount of the other reactant, since the two reactants usually form a bond with help of one or more valence electrons. The valence electrons are electrons, which are divided by atoms so they have full electron "shells". These shells need to have a certain number of electrons to make their shells full. This can be achieved through valence electrons, which are used at reactions so the reactants bind together.

There are more types of how the reactants can react together, the ionic bonding (non-metals with metals), the covalent bonding (non-metals with non-metals) and the metallic bonding (metals with metals).

The ionic bonds result in ionic compounds. Ionic bonds happen when non-metal elements donate their electrons to either alkali metals or alkaline metals. This leads to the non-metals becoming cations, positive ions, and the metals anions, negative ions. The ions are so arranged, that the negative and positive charges of the resulting structures balance each other, which leads to the compounds not falling apart.

The covalent bonds are similar to the ionic bonds: a pair of electrons is shared between two elements, always non-metals. Covalent bonds are directional, that means the atoms have specific orientations to each other. The resulting compounds also have lower energy than the elements separated.

The metallic bond is a bond, that results into a compound consisting of metals. These solids consist of closely packed atoms. Usually the outermost shell of each atom overlaps with the other outermost shells. As a consequence, the valence electrons move constantly from one atom to another. The electrons aren't localized, capable of wandering the whole crystal. Due to this, the compounds usually have a very high electrical conductivity.

There are two types of reactions: exothermic reactions and endothermic reactions. The exothermic reactions release heat and consequently make the surroundings warmer after the small input of energy which starts the reaction, since the reactants have energy "stored" in them, e.g. combustion. The endothermic reactions need energy, since they don't have enough of it "stored", so it gets absorbed from the surroundings, e.g. photosynthesis. The type of energy needed is the thermal energy.