Quantitative Analysis Flashcards
Flame test procedure
Dip a clean piece of nichrome/platinum wire into concentrated HCl (remove impurities)
Dip wire into salt sample being tested
Hold wire in non-luminous flame in a bunsen burner
Observe the color
Nichrome/platinum are inert and have a high melting point
Lithium flame test
Liverpool
Red
Sodium flame test
baNaNa
yellow
Potassium flame test
P for Purple
Lilac
Calcium flame test
Ca-rrot
Orange-red
Copper flame test
CuCurella - Chelsea (home + keeper kit)
Blue/green
Ammonium test
Add NaOH and warm gently
Characteristic smell of ammonia
NH3 gas turns red litmus blue
NH3 + H2O
Copper test
Add NaOH
C for Chelsea = Blue precipitate
Cu(OH)2
Iron (II) test
Add NaOH
Fe-ces = Green precipitate
Fe(OH)2
can be oxidised to Iron (III) by air
Iron (III) test
Add NaOH
Rust e e e = Orange-brown precipitate
Fe(OH)3
Any test looking for a precipitate must be carried out with salt in what form?
Solution of the salt
Chloride/Bromide/Iodide test
Add dilute nitric acid (remove CO3^-2 impurities)
Add silver nitrate solution
Milk - White precipitate AgCl
Cream - Cream precipitate AgBr
Cheese - Yellow precipitate AgI
(going down halogens)
Why can’t you use HCl when testing for halogens?
HCl contains chloride ions, which will react with the silver nitrate solution to form a precipitate
(false positive)
Carbonate test
Add dilute hydrochloric acid
Bubble gas produced through limewater
White precipitate with limewater (CO2 gas)
Sulfate test
Add dilute hydrochloric acid
Add aqueous barium chloride
Baaaaa - rium (sheep) chloride = White precipitate
BaSO4
Hydrogen gas test
Add lit splint to end of test tube
Squeaky pop
Oxygen gas test
Add glowing splint
Relights glowing splint
Chlorine gas test
Add moist litmus paper
Turns bleached
Ammonia gas test
Add moist red litmus paper
Turns blue
Carbon dioxide gas test
Bubble through limewater
White precipitate formed
Water test using anhydrous copper (II) sulfate
Add liquid to anhydrous copper (II) sulfate (white)
If water is present, colour changes from white to blue
(Works for anything containing water i.e. aqueous)
Physical test to show water is pure
Measure boiling/freezing point
If substance boils at 100°C or freezes at 0°C, it is pure water
Copper Carbonate color
Green
Copper Oxide color
Black
