6.2 Compound and mixture

A compound is a chemical substance made up of 2 or more different types of atoms that are chemically bonded with a forces holding them very strongly. It means the properties that are different to element that it’s made from. Contains a set ratio which is fixed, properities are different from other elements, its constituents are separated by chemical methods only like electrolysis, it is always homgoeneous(unifrom distribution of particles). mixtures composition of elements are not in a fixed ratio, show the properties of all its constituent elements, separated by physical methods like sieveing or distillation, they can be homogenous or heterogeous (either type of particle distribution).MOLECULAR COMPOUNDS: All the molecules of a compound are identical in size and shape and have the same number of atoms.​

• Examples of Molecular compounds:​

• Carbon Monoxide (contains one carbon atom and one oxygen atom​

• Water ( Two hydrogen atoms and one oxygen atom )​

• Glucose ( 6 carbon , 12 hydrogen, 6 oxygen)

• There are six main elements found in the body:​

  ​

  • Oxygen ​

  • Carbon ​

  • Hydrogen ​

  • Calcium ​

  • Nitrogen ​

  • phosphorous ​

  • ​

  • These simple elements combine forming different compounds.​Elements have different physical and chemical properties to the compounds they are found in.​

  • For eg. Sodium metal is very soft and corrodes quickly with oxygen. The sodium found in table salt (sodium chloride)has unique properties to the elements found individually. ​

  • Sodium atoms form sodium metal, a soft, silvery-white metal that burns vigorously in air and reacts explosively withwater. ​

  • Chlorine atoms form chlorine gas at room temperature and is a yellow gas that is extremely corrosive to most metalsand poisonous to living things. The vigorous reaction between the elements sodium and chlorine forms the white,crystalline compound sodium chloride, common table salt, which contains sodium cations and chloride anions. ​

  • The compound composed of these ions exhibits properties entirely different from the properties of the elements sodiumand chlorine.\Compounds can also form crystal lattices. In theselattices the atoms are bonded very strongly to each otherso they form very hard solids.​

  • Salt – sodium chloride (NaCl) and beach sand –Silica (SiO2) are examples of compounds that form acompound lattice. ​

  • Since the crystal lattice is very large, the formula ofthe compound gives you the ratio of each element presentin the compound, not the actual amount of each atom. ​

  • For every atom of sodium, there is one atom ofchlorine.