chemical analysis Flashcards
what is a pure substance
contains only one type of element or compound, so they melt and solidify and boil and condense at one temp
what is a formulation
mixture that has been carefully designed as a useful product
examples of formulations
fuels, medicines, alloys
what does chromatography include
stationary phase (doesn’t move) mobile phase (does move)
in paper chromatography, what is the stationary and mobile phase
stationary- absorbent paper
mobile- solvent (often water)
what happens during chromatography
- mixtures are separated into their individual component
- solvent dissolved the samples and carried them up the paper
- each component moves a different distance up the paper depending on its attraction for the paper and solvent
what an chromatography be used for
identity artificial colours (eg in food) by comparing them to results obtained from known substances
equation for calculating Rf value
distance moved by substance
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distance moved by solvent
what can Rf values be used for
identifying components in a mixture
gas test and result for hydrogen
(RED)
- squeaky pop test
- combines with oxygen when ignited
gas test and results for oxygen
(BLUE)
-relighted glowing splint
gas test for CO2 and results
(GREEN)
- limewater
- goes cloudy
gas test and results for Cl2 (chlorine)
(PURPLE)
-bleaches litmus paper from purple to white
