4.6 Chemical Analysis Flashcards
How do you conduct a flame test
Dip platinum wire into hydrochloric acid
dip wire into a sample of solid or solution
Place tip of wire into non-luminous Bunsen burner
What colour is Lithium’s flam e
Red
What Colour is Sodium’s flame (Na)
Yellow
What colour is Potassium flame (k)
Lilac
what colour is Ca (Calcium) flame
Orange-Red
What colour is Cu flame ( copper)
Blue- Green
How do you conduct a sodium Hydroxide test
Dissolve sample in water
add a few drops of sodium hydroxide
What colour precipitate is Fe2+(sodium hydroxide)
Green Fe(OH)2
What colour precipitate is Fe3+ (sodium Hydroxide)
Brown Fe(OH)3
what colour precipitate is Cu2+ (sodium hydroxide)
Blue Cu(OH)2
What is the test for Ammonium test
Dissolve sample in water
Add sodium hydroxide and warm it
Test gas evolved with damp red litmus paper
What is a positive Ammonium test
Turns damp red litmus paper to blue
How do you test for halides
Dissolve the sample in water
Add nitric acid
Add silver nitrate solution
What colour is Cl - precipitate and its’ formular (for a halides test)
White
AgCl
What colour is Br - precipitate
Cream
AgBr
What colour is I- precipitate for a halide test
Yellow
AgI
How do you carry out the test for Carbonates
Add hydrochloric acid
If there is effervescence, bubble gas through limewater
turns cloudy if carbonate
Describe the test for sulphates
Add Hydrochloric acid
If there is no effervescences add barium chloride
forms a white percipitate
What is the colour of the precipitate for barium Chloride
White precipitate
Why is it important to check if there is no effervensence
to prevent false positives
Carbonate ions also forms a white precipitate
