Carboxylic acids
The A homologous series of compounds that contain the carboxyl functional group, -COOH. form a A 'family' of organic compounds that have the same functional group and similar chemical properties. . Like all homologous series, the carboxylic acids:
- have the same An algebraic formula that sets out a rule or trend which is followed by all members of a homologous series. For example, all non-cyclic alkanes have the general formula CnH2n+2.
- differ by CH2 in molecular Chemical formula showing the actual number of atoms of each element in a molecule. from neighbouring A substance formed by the chemical union of two or more elements.
- show a gradual variation in physical The characteristics of something. In chemistry, chemical properties include the reactions a substance can take part in. Physical properties include colour and boiling point., such as their The temperature at which a substance rapidly changes from a liquid to a gas.
- have similar chemical properties
Functional group
The An atom, or group of atoms, that determines the main chemical properties of an organic compound. in the carboxylic acids is the A functional group found in the carboxylic acids, -COOH. group, -COOH. It is responsible for the typical reactions of carboxylic acids, which are weak Substance producing more hydrogen ions than hydroxide ions when dissolved in water. . Vinegar is a dilute solution of ethanoic acid.
Structures
The table shows four carboxylic acids, their molecular formulae and their structures.
Acid properties
The carboxylic acids have the typical properties of acids. For example, they:
- When a substance breaks up and mixes completely with a solvent to produce a solution. in water to form Having a pH lower than 7.Mixture formed by a solute and a solvent. with Scale of acidity or alkalinity. A pH (power of hydrogen) value below 7 is acidic, a pH value above 7 is alkaline. values less than 7
- react with Shiny element that is a good conductor of electricity and heat, and which forms basic oxides. to form a The substance formed when the hydrogen ion in an acid is replaced by a metal ion. and hydrogen
- react with A substance that reacts with an acid to neutralise it and produce a salt. to form a salt and water
- react with carbonates to form a salt, water and carbon dioxide
These properties are due to the -COOH functional group.