Topic 8 - Chemical Analysis Flashcards
Chromatogram
A graph that shows the result of separating the components of a mixture by
chromatography.
Chromatography
A technique used to separate mixtures due to the distribution of the
substances between the stationary and mobile phase. It can give information to help identify
substances.
Flame emission spectroscopy
An instrumental method used to analyse metal ions in
solutions.
Flame test
Qualitative test used to identify metal ions (cations). Carried out by inserting a
nichrome wire loop with the unknown compound on into a flame and observing the colour.
Formulation
A mixture that has been designed as a useful product. They are made by
mixing the components in carefully measured quantities to ensure that the product has the
required properties.
Impure substance
A substance made up of two or more elements or compounds that are
not bonded together chemically.
Instrumental methods
Instrumental methods can be used to detect and identify elements
and compounds. They are accurate, sensitive and rapid.
Litmus paper
Paper stained with litmus which can be used to indicate the acidity or
alkalinity of a substance. Used in the test for chlorine.
Mobile phase
Where the molecules can move during chromatography. It is always a liquid
or gas.
Precipitation
The creation of a solid from a solution.
Pure substance
In chemistry a pure substance is a single element or compound, not mixed
with any other substance. In everyday language, a pure substance can mean a substance
that has had nothing added to it, so it is unadulterated and in its natural state.
Rf value
The ratio of the distance moved by a compound to the distance moved by the
solvent.
Stationary phase
Where the molecules are stationary during chromatography. It is a solid
or a liquid supported on a solid.
