Chemical analysis Flashcards
what is a pure substance
something made of only one type of substance
what is the difference between the melting an boiling points of a pure and impure substance
pure - sharp/ one specific temp
impure - broad/ occurs across a range of temps
what is a formulation
a mixture designed for a specific purpose
what are some examples of formulations
fuels, cleaning agents, paints, medicines, foods and fertilisers
what is chromatography
a process for separating coloured mixtures
how is Rf calculated
distance moved by substance/ distance moved by solvent
what is the test for hydrogen
a lit splint gives a squeaky pop
what is the test for oxygen
re lights a glowing splint
what is the test for carbon dioxide
turns limewater milky if bubbled through it
what is the test for chlorine
bleaches damp litmus paper
what is the test for aluminium, calcium and magnesium ions
forms white precipitate with sodium hydroxide solution
how can aluminium ions be distinguished from calcium and magnesium
the white precipitate dissolves with excess sodium hydroxide
what colour precipitates are formed when sodium hydroxide solution is added to solutions of copper, iron II and iron III ions
copper - blue
iron II - green
iron III - brown
what is the test for a halide ion
add silver nitrate and nitric acid: chloride forms white precipitate, bromide forms cream precipitate and iodide forms yellow precipitate
what is the test for a carbonate ion
carbon dioxide gas formed on addition of acid
