Composition of MIxtures

Composition of MIxtures

Mixtures

  • A mixture refers to the combination of two or more substances that do not chemically react with each other and thus, can be separated.
  • Each substance within a mixture retains its own set of properties. For example, in a mixture of sand and water, sand remains insoluble and water remains a liquid.
  • Mixtures can either be homogeneous or heterogeneous.
  • Homogeneous mixtures are those where the different substances are fully mixed and the mixture appears the same throughout.
  • Heterogeneous mixtures are those where the substances do not mix fully, resulting in different parts of the mixture showing different properties.

Separation Techniques

  • Various techniques can be used to separate mixtures based on the properties of the substances involved.
  • Filtration is used to separate a solid from a liquid in a heterogeneous mixture. For instance, sand can be separated from water through filtration.
  • Evaporation is used to separate a solvent from a solution. It relies on the fact that the solvent has a lower boiling point than the solute.
  • Distillation is a process used to separate the components in a liquid mixture. It involves heating the mixture to create vapour and then cooling that vapour to create a liquid.
  • Chromatography is a separation technique that separates components of a dissolved mixture based on their different degrees of absorption.
  • The method of centrifugation involves the use of the centrifugal force for the separation of mixtures with components of different densities. It is commonly used for the separation of cream from milk.

Properties of Mixtures

  • The properties of a mixture are derived from the properties of its components. For instance, a mixture of sand and water would be partly solid (sand) and partly liquid (water).
  • Mixing substances can sometimes result in changes to their properties. For example, salt dissolves in water to form a clear, homogeneous mixture.
  • Mixtures are not represented by chemical formulas as they are not chemically combined. Each component maintains its own chemical identity.
  • The proportions of substances in a mixture can be varied. This contrasts with compounds, where the proportions of elements are fixed.