What are empirical formulas?

Empirical formulas describe the ratio of each type of atom in the substance. The word "empirical" refers to the origin of empirical formulas in observable results; This means that the formulas are determined by the experiment. Scientists test the composition of unknown compounds by observing their formation or their interactions with known substances. The ratio of atoms in the compound gives only a gross idea of ​​its nature, but it is the basis for further exploration. They perform a reaction to the production of the product without leaving no undeveloped inputs. They also monitor the proportions of agents that move to the reaction. It is important that they know the proportion of reagent molecules rather than the proportion of weight or volume, because these measurements may vary for different molecules. The share of the reagents tells them that the share of atoms in the product, because all the molecules that have inserted are used in response.

Another way to determine empirical formulas is to cause the compound to respond with a different substance and observe the products of the reaction. Scientists usually use this method to analyze hydrocarbons,substances that contain only carbon and hydrogen atoms. They burn unknown hydrocarbons and collect carbon dioxide and water evaporation.

when the hydrocarbon burns, it reacts with oxygen; The reaction can be represented as c _{f h g + b o 2 -D what 2 + e h o, where A, B, D and E indicate the proportions of molecules in responses A F and G in Hydrocan. The experimenters measure carbon dioxide and water vapor. Then Onirozel these numbers with the molecular weight of the compounds. For carbon dioxide, the resulting number is the same as the number of carbon atoms, but must multiply the number of water molecules to obtain the number of hydrogen molecules. They will find the smallest integers that maintain the share of C and H, and these are F and G in the equation: subscription empirical formulas.}

Empirical formulas do not mean the exact structure of the molecule. For example, acetylene and benzene are hydrocarbons that obsThe same number of atoms of carbon and hydrogen atoms, so the empirical formula of each is ch. The molecular formula of the acetylene is C _{2 h 2 , while benzene is c 6 They have extremely different properties, although they have the same empirical formula. Acetylene is a highly explosive gas used for cutting and welding; Six -necked benzene rings are a definitive component of aromatic substances and are present from the molecules responsible for tastes and smells.}