C12 Flashcards
what is a pure substance
a substance that is made up of just one element or compound
what is the test for pure water
test if its melting and boiling point is 0 degrees and 100 degrees
how can you use melting and boiling points to identify pure substances
pure substances have specific melting and boiling points
what do impurities do
lower the melting point and raise the boiling point
what is a formulation
a mixture that has been designed to produce a useful product
give some examples of a formulation
paint
binder - helps paint attach to the object
solvent - helps paint spread
what is the mobile phase and paper in paper chromatography
the solvent is mobile phase
paper is the stationary phase
what does the solvent do in paper chromatography
moves through the paper carrying different substances different distances
what substance will travel further in paper chromatography
a substance with stronger forces of attraction to the solvent than the paper
the more soluble it is
what is the equation of the rf value
distance moved by substance / distance moved by solvent
how do we test for hydrogen
collect a test tube of gas
hold a lighted splint at the open of the test tube
if the gas burns quickly with a squeaky pop hydrogen is present
how do we test for oxygen
insert a glowing splint in the mouth of a test tube
if the glowing splint relights oxygen is present
how do we test for carbon dioxide
bubble the gas through limewater
if limewater turns milky co2 is present
how do we test for chlorine
a piece of damp blue litmus paper is held in the mouth of a test tube
if the paper gets bleached and turn white chlorine is present
how can some positive ions be identified
using a flame test or by using sodium hydroxide solution
what colours do lithium potassium sodium calcium and copper make when burnt
lithium - crimson
sodium - yellow
potassium - lilac
calcium - orange/red
copper - greem
why does a precipitate of the metal hydroxide usually form when you add solution to ions with 2+ or 3+
ions with = and 3+ are insoluble in water
what do calcium, aluminium and magnesium ions all form
they form white precipitates of their ions
what colour does copper iron(II) and iron(III) create if you add sodium hydroxide
copper II - a blue precipitate
iron II - green precipitate
iron III - brown precipitate
