chemical analysis Flashcards
definition of mixture
different substances mixed which are usually easy to separate
definition of a compound
different elements chemically joined together
definition of pure
a single element or compound that is not mixed with any other substance
how can u tell if a substance is pure
it has a sharp melting and boiling point
the freezing point of a pure substance is the _______ as its melting point
same
how is a formulation made
by mixing the components in carefully measured quantities to ensure that the product has the required properties
definition of a formulation
a mixture that has been designed as a useful product made by mixing the components in carefully measured quantities to ensure that the product has the required properties
definition of a solute
solid that dissolves in a solvent
definition of a solvent
liquid into which a solute dissolves
definition of a solution
formed when a solute dissolves in a solution
how to separate salt from sand
- grind up rock salt mixture using a mortar and pestle
- place rock salt into a beaker and acid and add 25 cm3 of water
- stir using a stirring rod until all the salt has dissolved
- filter the solution to removed the rock and sand and collect the filtrate in an evaporating basin
- heat using a Bunsen, tripod and gauze to evaporate the water
- allow to cool and crystallise
what do you draw the line with in chromatography and why
pencil because if ink was used it could separate and interfere with the results
where is the pencil line drawn and why
above the solvent otherwise the substances being tested would run into the solvent instead of travelling up the paper
how do u know if it is a pure substance in chromatography
there will only be one spot
mobile phase
solvent
stationary phase
the paper
what does rf stand for
retardation factors