C12 - Chromatography + pure substances Flashcards
pure substance
made up of one substance only
either an element or compound
impure
mixture of 2 or more elements/compounds
identify pure substances
by their boiling points/ melting
pure substance bioling point
sharp
impure substances boiling point
vary over a range
impurities effect on boiling and melting points
-lowers melting point
-raises boiling point
test for pure water
-melts at 0 degrees celsius
-boils at 100 .c
purer the compound =
narrower the melting point range
formulation
-mixture that has been designed to produce a useful product
eg of formulations
-paint
-medicinal drugs
-fuels
-fertilisers
-cosmetics
-food products
paint formulations
-pigment
-binder
-solvent
pigment
-provides colour
binder
allows paint to attach to object and dry to form a protective film
solvent
-help pigment/ binder to spread well
cleaning products: surfactant
detergent
cleaning products: water
thins mixture
cleaning products: colouring/frangance
makes it more appealing to buyer
cleaning products: rinse agent
-helps water to drain off
chromatography
separates/ identifies mixtures that are unknown
-used for ink
a substance with a stronger force of attraction between itself and mobile phase
travels a greater distance in a given time
mobile phase
moves through stationary phase
-carries components
-solvent
when does the spot not travel as far in chromatography
-stronger force of attraction to stationary phase
stationary phase
paper
mixture shows
more than 1 spot formed
pure spots show
1 spot
how to identify elements
compare known spots with unknown ones
retention factor equation
distance moved by substance / distance moved by solvent
