Chemical Anaylsis Flashcards
whats something thats pure?
only one compound or element.
how can you test the purity of a substance?
measure its mp or bp and compare it to mp and bp of pure substance.
what do impurities increase?
the boiling point.
how are formulations important in the pharmaceutical industy?
by altering formulation of a pill chemists can make sure it delivers to right part of body at right concentration.
where are formulations found in everyday life?
cleaning products, fuels, cosmetics, fertilisers, metal alloys, food and drink.
whats chromatography used for?
analytical method used to separate substances in a mixture.
whats the mobile phase?
molecules can move, liquid or gas.
whats the stationary phase?
molecules cant move, solid or really thick liquid
what happens to the chemicals that spent more time in the mobile phase?
they will move further through the stationary phase.
in paper chromatography what is the stationary phase and what is the mobile phase?
stationary phase- chromatography paper
mobile phase- solvent e.g ethanol or water
whats the Rf value?
distance travelled by substance/ distance travelled by solvent
whats the result of a chlorine test?
bleached litmas paper
oxygen present?
relight a glowing splint
carbon dioxide present?
turns limewater cloudy.
hydrogen present?
squeaky pop
how can you test for carbonates?
Put sample in test tube.
use pipette to add dilute acid
connect with test tube of limewater
if carbonate is present carbon dioxide will be released turning limewater cloudy.
what precipitate is formed from barium sulfate?
a white precipitate.
how do you test for halides?
add dilute acid and silver nitrate solution
what precipitate is formed from silver chloride?
white
what precipitate is formed from silver bromide?
cream
what precipitate is formed from silver iodide.
yelllow
what colour do lithium ions burn with?
crimson
what colour do sodium ions burn with?
yellow
what colour do potassium ions burn with?
lilac
what colour do calcium ions burn with?
orange-red flame
what colour do copper ions burn with?
green flame
how do you clean the wire loop for the flame test?
dip loop in dilute HCI then hold it in blue flame until it burns with no colour.
what precipitate does calcium form?
white
what precipitate does copper (II) form?
blue
what precipitate does Iron (II) form?
green
what precipitate does Iron (III) form?
Brown
what precipitate does aluminium form?
white and first, redissolves in excess to form colourless solution
what precipitate does Magnesium form?
white
what happens during flame emission spectroscopy?
sample placed in flame
ions heat up and electrons become excited
electrons drop back to originals energy levels
energy is then transfered as light
light passed spectroscope, detect different wavelengths of light to produce line spectrum
what does the intensity of the light spectrum indicate?
concentration of that ion in solution
what are advantages of instrumental analysis?
very sensitive, very fast, very accurate
