2. METHODS OF SEPARATING AND PURIFYING MATTER Glossary GCSE EDEXCEL CHEMISTRY

Glossary

1. atom
   The smallest part of an element that can exist.
2. boiling point
   The temperature at which a substance rapidly changes from a liquid to a gas.
3. chromatogram
   The results of separating mixtures by chromatography.
4. chromatography
   Chromatography is used to separate different substances dissolved in a liquid.
5. compound
   A substance formed by the chemical union of two or more elements.
6. concentration
   The concentration of a solution tells us how much of a substance is dissolved in water. The higher the concentration, the more particles of the substance are present.
7. condensed
   Turned from a gas or vapour into a liquid, usually as a result of cooling.
8. crude oil
   Mixture of hydrocarbons, mainly alkanes, formed over millions of years from the remains of ancient dead marine organisms.
9. crystal
   A solid containing particles (atoms, molecules or ions) joined together to form a regular arrangement or repeating pattern.
10. crystallisation
    The process of producing crystals from a solution by evaporating the solvent.
11. dissolved
    A substance is said to be dissolved when it breaks up and mixes completely with a solvent to produce a solution.
12. element
    A substance made of one type of atom only.
13. ethanol
    The alcohol which is produced as a result of fermentation of sugars by yeast.
14. evaporation
    The process in which a liquid changes state and turns into a gas.
15. excess
    In chemistry, a substance is in excess if there is more than enough of it to react with another reactant.
16. filtration
    Method used to separate an insoluble solid from a liquid using a physical barrier such as paper.
17. fraction
    In fractional distillation, such as that of crude oil, the different parts of the original mixture are called fractions. The substances in each fraction have similar boiling points to each other.
18. fractional distillation
    In fractional distillation a mixture of several substances, such as crude oil, is distilled and the evaporated components are collected as they condense at different temperatures.
19. freeze
    A change of state in which liquid becomes solid by cooling.
20. groundwater
    Where water is stored in rocks beneath the ground.
21. insoluble
    Unable to dissolve in a particular solvent. For example, sand is insoluble in water.
22. ion
    Electrically charged particle, formed when an atom or molecule gains or loses electrons.
23. melting
    The process that occurs when a solid turns into a liquid when it is heated.
24. melting point
    The temperature at which a solid changes into a liquid as it is heated.
25. micro organisms
    Microscopic living things such as archaea, bacteria and some species of eukaryotes. 
26. mixture
    Two or more substances that are not joined together. The substances can be elements, compounds, or both.
27. mobile phase
    Phase in chromatography that moves, usually a solvent or mixture of solvents.
28. molecule
    A collection of two or more atoms held together by chemical bonds.
29. particle
    A general term for a small piece of matter. For example, protons, neutrons, electrons, atoms, ions or molecules.
30. potable
    Water that is safe to drink.
31. pure
    A substance that consists of only one element or only one compound.
32. reactant
    A substance that reacts together with another substance to form products during a chemical reaction. 
33. simple distillation
    Separation method used to separate a solvent from a solution.
34. soluble
    Able to dissolve in solvent. For example, sugar is soluble in water because it dissolves to form sugar solution.
35. solute
    The dissolved substance in a solution.
36. solution
    Mixture formed by a solute and a solvent.
37. solvent
    The liquid in which the solute dissolves to form a solution.
38. stationary phase
    Phase in chromatography that does not move, for instance, the paper in chromatography.
39. vapour
    Gas formed below the boiling point of a substance.