chemical analysis Flashcards
what is a pure substance
a single element or compound that isnt mixed with any other substance
How Can we check if a substance is pure?
melting or boiling points
What is formulation?
Formation is a mixture that has been designed as a useful product
Examples of formulation (paint )
Pigments
Solvent
Binder
Additives
What is chromatography
It is a metal used to separate substances in a mixture and identify the substances
What are these two stages of chromatography?
The mobile stage
Where the molecules can move
The stationary stage
Where the molecules can’t move
Calculate the Rf value
Distance travelled by substance /
Distance travelled by solvent
Test for chlorine
Doing bleacher dump, litmus paper, turning it white
It may turn red at first, but that’s because the solution is acidic
Test for oxygen
If you put a glowing splint inside a test to contain oxygen, oxygen will relies the glowing splints
Test for carbon dioxide
Bubbling carbon dioxide through an aqueous solution of calcium hydroxide causes the solution to turn cloudy
Test for hydrogen
If you lit splints at the open end of a test tube containing hydrogen, you’ll get a squeaky pop noise
Flame test
lithium compounds result in a crimson flame
sodium compounds result in a yellow flame
potassium compounds result in a lilac flame
calcium compounds result in an orange-red flame
copper compounds result in a green flame
Metal hydroxides
Calcium, Ca2+. White
Copper(II), Cu2+. Blue
Iron(II), Fe2+. Green
Iron(III), Fe3+. Brown
Aluminium, Al3+ white then colourless
Magnesium, Mg2+ White
Ca^ 2+ (aq) +2OH^ - (aq) >Ca(OH) 2( bullet)
Carbonates
Carbonate reacts with dilute acid to form carbon dioxide gas
carbon dioxide can be identified with lime water
Halides
Halides ions in solution produce precipitate with silver nitrate solution in the presence of dilute nitric
Silver chloride is white
Silver, bromide cream
Silver iodide is yellow
