The chemical compounds They are substances formed by two or more interrelated elements, which give rise to an entirely new and different substance. According to the type of atoms that make up these compounds, we can speak of organic and inorganic compounds. For instance: glucose, ethanol, ammonia, sulfuric acid.
The organic compounds They mainly contain carbon atoms combined with elements such as hydrogen, oxygen, nitrogen, and sulfur. These compounds have covalent bonds between non-metallic atoms and are of great diversity.
Most organic compounds derive from a group of compounds known as hydrocarbons, which are so named because they are made up of only hydrogen and carbon. Examples of hydrocarbons are: methane (CH4), propane (C3H8) and Acetylene (C2H2).
The chemistry of organic compounds is largely determined by functional groups, which consist of one or more specifically bonded atoms. The chemical properties of these molecules can be predicted based on the reactivity of the functional groups. The main organic compounds are: alcohols, ethers, aldehydes and ketones, carboxylic acids, esters and amines.
- Alcohols. They have the hydroxyl functional group —OH. For instance: methanol (CH3OH) and ethanol (C2H6OR).
- Ethers. They contain the R — O — R ‘junction, where R and R’ are hydrocarbons. For instance: diethyl ether (C2H5OC2H5), which is used as a grease solvent.
- Aldehydes and ketones. They have the carbonyl functional group, —CO—. In an aldehyde there is at least one hydrogen atom attached to the carbon of the carbonyl group. For instance: formaldehyde (CH2OR). In a ketone, the carbon atom of the carbonyl group is attached to two hydrocarbon groups. For instance: propanone (C3H6OR).
- Carboxylic acids. They are acids that contain the carboxyl group, —COOH. For example: methanoic acid, also called formic acid (HCOOH), which is the acid present in the venom that ants inject, and ethanoic acid, also called acetic acid (CH3COOH), which is the main component of vinegar.
- Esters. They have the general formula R’— COO — R, where R ‘can be H or a group derived from a hydrocarbon, and R is a group derived from a hydrocarbon. Esters are used in the manufacture of perfumes and as flavoring agents. The aroma of fruits is mainly due to the esters they contain. For example, bananas contain 3-methylbutyl acetate [CH3COOCH2CH2CH(CH3)2]; oranges contain octyl acetate (CH3COOCHCH3C6H13) and the apples contain methyl butyrate (CH3CH2CH2COOCH3).
- Amines. They are organic bases that have the general formula R3N, where R can be H or a group derived from a hydrocarbon. For instance: the anilines, which are used mainly in the production of colorants.
Organic chemistry studies the compounds of carbon. Chemists in the 18th century used the word “organic” to describe substances obtained from living things. These chemists believed that they could only produce organic compounds from nature. But this conception was discarded in 1828 when urea, an organic compound, could be synthesized from the reaction of two inorganic compounds. At present, more than 20 million synthetic and natural organic compounds are known. This number is much higher than the approximately 100,000 known inorganic compounds.
They do not usually contain carbon atoms, nor hydrogen-carbon bonds (typical of hydrocarbons). For convenience, some carbon-containing compounds are considered inorganic compounds, such as carbon monoxide (CO), carbon dioxide (CO2), carbon disulfide (CS2), compounds containing the cyanide group (CN–), as well as carbonate groups (CO32-) and bicarbonate (HCO3–).
The atoms of inorganic compounds can be linked by ionic (metallic and non-metallic atom) or covalent bonds. These substances can contain multiple elements from any source on the periodic table.
Inorganic compounds are divided into four categories: ionic compounds, molecular compounds, acids and bases, and hydrates.
- Ionic compounds. They are made up of positive ions (cations) and negative ions (anions). Ionic compounds are good electrical conductors when dissolved in water. For instance: sodium chloride (NaCl), zinc iodide (ZnI2) and potassium cyanide (KCN).
- Molecular compounds. They are made up of non-metallic elements. Many molecular compounds are binary compounds – they are made up of two atoms. For instance: silicon carbide (SiC) and hydrogen bromide (HBr).
- Hydrates. They are compounds that have a specific number of water molecules attached to them. For example, in its normal state, each unit of copper (II) sulfate has five water molecules associated with it. The name of this compound is copper (II) sulfate pentahydrate, and its formula is written as CuSO4 5H2O. When the water molecules are removed, the resulting compound is CuSO4, which is usually called anhydrous copper (II) sulfate; the word “anhydrous” means that the compound no longer has water molecules attached to it. Other examples of hydrates are barium chloride dihydrate (BaCl2 2H2O) and strontium nitrate tetrahydrate (Sr (NO3)2 4H2OR).
- Acids and bases. An acid is described as a substance that releases hydrogen ions (H+) when dissolved in water. For example: hydrochloric acid (HCl), phosphoric acid (H3PO4) and sulfuric acid (H2SW4). A base is described as a substance that releases hydroxide ions (OH–) when dissolved in water. For example: sodium hydroxide (NaOH), potassium hydroxide (KOH), and barium hydroxide [Ba(OH2)].
Examples of organic compounds
- Methanol (CH3OH). Known as wood or methyl alcohol, it is the simplest alcohol there is.
- Propanone (C3H6OR). The common solvent acetone, flammable and transparent, with a characteristic odor.
- Acetylene (C2H2). Also called ethyne, it is an alkyne gas lighter than air and colorless, highly flammable.
- Ethyl ethanoate (CH3-COO-C2H5). Also known as ethyl acetate or vinegar ether, it is used as a solvent.
- Formol (CH2OR). Used as a preservative of biological matter (samples, corpses), it is also known as methanal or formaldehyde.
- Glycerin (C3H8OR3). Also called “glycerol” or “propanetriol”, it is an intermediate product of alcoholic fermentation and digestive processing of lipids.
- Glucose (C6H12OR6). It is a monosaccharide or simple sugar, which constitutes the basic unit of energy in living beings.
- Ethanol (C2H6OR). It is ethyl alcohol, present in alcoholic beverages, the result of the anaerobic fermentation of sugars with yeast.
- Isopropanol (C3H8OR). Isopropyl alcohol, an isomer of propanol, becomes acetone upon oxidation.
- Acetylsalicylic acid (C9H8OR4). It is the active compound of aspirin: analgesic, antipyretic, anti-inflammatory.
- Sucrose (C12H22OReleven). It is a disaccharide made up of glucose and fructose. The most common of the carbohydrates is table sugar.
- Fructose (C6H12OR6). It is the sugar in fruits, and maintains an isomeric relationship with glucose.
- Cellulose (C6H10OR5). It is the main compound of plant beings, and serves as a structure in the plant cell wall.
- Nitroglycerin (C3H5N3OR9). It is a powerful explosive, and is obtained by mixing concentrated nitric acid, sulfuric acid and glycerin.
- Lactic acid (C3H6OR3). The production of glucose via lactic fermentation is essential in energizing processes of the human body in the face of low oxygen concentrations.
- Benzocaine (C9HelevenNO2). It is used as a local anesthetic, although its use in infants has high toxicity as a side effect.
- Lidocaine (C14H22N2OR). It is an anesthetic, widely used in dentistry and as an antiarrhythmic.
- Lactose (C12H22OReleven). Formed from galactose and glucose, it is the sugar that gives animal milk its energy load.
- Cocaine (C17Htwenty-oneNO4). It is a powerful alkaloid derived from the coca plant and synthesized to produce an illegal drug of the same name.
- Ascorbic acid (C6H8OR6). Also known as the important vitamin C of citrus fruits.
Examples of inorganic compounds
- Sodium Chloride (NaCl). It is common table salt.
- Hydrochloric acid (HCl). It is one of the most powerful acids known, secreted by the stomach to digest food.
- Phosphoric acid (H3PO4). It is a water-reactive acid, resistant to oxidation, evaporation and reduction, used in the soft drink industry.
- Sulfuric acid (H2SW4). It is one of the largest known corrosives, widely used in various types of industry and is produced in large quantities in the world.
- Potassium Iodide (KI). It is a salt widely used in photography and in radiation treatment.
- Potassium dichromate (K2Cr2OR7). It is an orange salt, highly oxidizing, capable of causing fires when in contact with organic substances.
- Silver chloride (AgCl). Widely used in electrochemistry and laboratories. Due to its very low solubility in water, it is a crystalline solid.
- Ammonia (NH3). Also called “azano” or “ammonium gas”, it is a colorless gas rich in nitrogen, with a particularly repulsive odor.
- Cuprous sulfate (Cu2SW4). It is an insoluble salt, used as a disinfectant and colorant for metal surfaces.
- Silicon oxide (SiO2). Commonly called “silica”, it forms quartz and opal, and is one of the components of sand.
- Iron sulfate (FeSO4). Also known as green vitriol, melanterite or green caparrosa, it is a blue-green salt used as a colorant and as a treatment for certain anemias.
- Calcium Carbonate (CaCO3). Long used as an antacid and in the glass and cement industry, it is a very abundant substance in nature (present in rocks, shells and exoskeletons of certain animals).
- Lime (CaO). It is calcium oxide in any of its forms, widely used in construction mixtures as a binder.
- Sodium bicarbonate (NaHCO3). Present in fire extinguishers or in many dietary and medicinal products, it has a very alkaline pH.
- Potassium hydroxide (KOH). It is potassium soda, used in the manufacture of soaps and other solvents.
- Sodium hydroxide (NaOH). Called caustic soda or caustic soda, it is used in the paper, fabric and detergent and drain opener industries.
- Ammonium nitrate (NH4NO3). It is a powerful agricultural fertilizer.
- Cobalt Silicate (CoSiO3). It is used in the production of pigments (such as cobalt blue).
- Magnesium sulfate (MgSO4). It is Epsom salt or English salt, when adding water. It has multiple medical uses, especially muscular, or as bath salts.
- Barium chloride (BaCl2). It is a very toxic salt used in pigments, steel treatments, and fireworks.
- Chemistry. Chang R., Goldsby K. (2013). elevenhe edition. Mc Graw-Hill Publishing House