text: All mixtures can be characterized as being separable by mechanical means (e.g. purification, distillation, electrolysis, chromatography, heat, filtration, gravitational sorting, centrifugation). Mixtures differ from chemical compounds in the following ways:
  * the substances in a mixture can be separated using physical methods such as filtration, freezing, and distillation.
  * there is little or no energy change when a mixture forms (see Enthalpy of mixing).
  *The substances in a mixture keep its separate properties. 
  In the example of sand and water, neither one of the two substances changed in any way when they are mixed. Although the sand is in the water it still keeps the same properties that it had when it was outside the water.
  * mixtures have variable compositions, while compounds have a fixed, definite formula.
  * when mixed, individual substances keep their properties in a mixture, while if they form a compound their properties can change.
  The following table shows the main properties and examples for all possible phase combinations of the three "families" of mixtures: