Chemistry Formulas

Chemical Formula

The chemical formula is a method of providing information about the chemical proportions of atoms that make a particular chemical compound or molecule by chemical elements numbers and symbols. Furthermore, the chemical formula is not a chemical name and it contains no words. But, it suggests the simple chemical structures, also it is not same as the full chemical structural formula. Moreover, it simply specifies the simplest of molecules and chemical substances.

Empirical Formula

It is the simple representation of the relative number of each type of atom or ratio of the elements in the compound. In addition, they are the standard for ionic compounds, such as CaCl2 and for macromolecules such as SiO2. Also, an empirical formula has no reference to isomerism, structure, or an absolute number of atoms.

Most noteworthy, the word empirical refers to the procedure of elemental study. It is a method of analytical chemistry that we use to determine the relative percent composition of a pure chemical substance by elements.

For example:

The empirical formula of hexane is C3H7. But its molecular formula is C6H14 and its structure is CH3CH2CH2CH2CH2CH3. In the same way, the empirical formula for hydrogen peroxide is H2O2. That is a simple HO that expresses the 1:1 ratio of components elements. Also, the acetic acid and formaldehyde have the same empirical formula that is CH2O.

Molecular formula

It indicates the simple number of all type of atom in a molecule of a molecular substance. Most noteworthy, they are same as empirical formulas for molecules that only have one atom of a particular type, but they have larger numbers.

Moreover, the molecular formula shows the number of elements in a molecule to determine if it is a binary compound, ternary compound, quaternary compound, or even more elements.

For example: The empirical formula of glucose is CH2O (ratio 1:2:1). On the other hand, its molecular formula is C6H12O6 (number of atoms 6:12:6).

Condensed formula

It may characterize the types and spatial arrangement of bonds in a simple chemical substance, however, is does not necessarily specify isomers or complex structures.

For example: Ethane consists of two carbon atoms that are single-bonded to each other. The carbon atom having three hydrogen atoms bonded to it. We can write its chemical formula as CH3CH3. Furthermore, in the same way, ethylene has a double bond between the carbon atoms, then the chemical formula is CH2CH2, and the fact that there is a double bond between the carbons is implicit because carbon has a valance of four. Besides, a more clear method is to write H2C=CH2 or less commonly as H2C::CH2.

Moreover, we can express a triple bond with three lines (HC≡CH) or three pairs of dots (HC:::CH), and if there may be uncertainty, a single line or pair of dots can be used to indicate a single bond.

Most noteworthy, molecules have multiple functional groups that are the same that we may express by enclosing the constant group in round brackets.

For example: We can write isobutene as (CH3)3CH. This condensed structural formula suggests diverse connectivity from other molecules that can form using the same atoms in the same proportions (isomers). Moreover, the formula (CH3)3CH suggest central carbon atoms connects to one hydrogen atom and three CH3 groups. Besides, we can use this to make a straight chains molecule, n-butane CH3CH2CH2CH3.

Solved Example for You

Question: Write some chemical formulas in the Hill system?

Answer: Some chemical formulas in Hill system are:

  • BrI
  • CCl4
  • CH3I
  • C2H5Br
  • H2O4S

Explanation: Hill system is the most commonly used system in the chemical database and printed indexes to sort lists of compounds. In this system, all the elements are arranged alphabetically in which single-letter comes first then two-letters and so on. In this way, ‘B’ comes first and then ‘Be’ and then ‘Br’ and so on.

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