Tests for ions and Flame Photometry (Acids 2) Flashcards
How do you carry out a flame test?
You would soak a splint in the solution that you are testing and then hold it IN a bunsen burner flame set to roaring
What colour flame does a lithium ion produce?
Red flame
What colour flame does a Sodium ion produce?
Yellow flame
What colour flame does a potassium ion produce?
Lilac flame
What colour flame does a calcium ion produce?
Orange/Red flame
What colour flame does a copper ion produce?
Blue/Green flame`
Are compounds of sodium potassium, and ammonium soluble?
All compounds of sodium, potassium and ammonium are soluble
Are nitrates soluble?
All nitrates are soluble
Are chlorides soluble?
All chlorides except for silver and lead chloride are soluble
Are sulfates soluble?
All sulfates except for barium, calcium and lead sulfate are soluble
Are carbonates soluble
All carbonates except for Sodium, potassium and ammonium are INsoluble
Are hydroxides soluble?
All hydroxides except for Sodium, potassium and ammonium hydroxides are INsoluble
How do you test for sulfate ions?
Add hydrochloric acid to the solution to acidify it and get rid of any carbonate ions (1). Then add Barium Chloride solution (1). If sulfate ions are present, a white precipitate of Barium Sulfate will form (1).
Barium sulfate is insoluble so will form a precipitate
What is the word equation with state symbols for the sulfate ion test?
Metal Sulfate(aq) + Barium Chloride(aq) –> Barium Sulfate(s) + Metal Chloride(aq)
Why is it safe to swallow toxic Barium Sulfate tablets?
Because Barium Sulfate is insoluble it won’t be absorbed into the bloodstream
How do you test for Halide Ions?
You first add nitric acid to react with any carbonate in the solution (1). You then add silver nitrate solution (1). If there is a halide ion present a coloured precipitate will form (1).
What colour precipitate will Chloride ions form?
A white precipitate of silver chloride
What colour precipitate will bromide ions form?
A cream coloured precipitate of silver bromide
What colour precipitate will iodide ions form?
A yellow precipitate of silver iodide
What is the equation for the test for chloride ions?
Ag+(aq) + Cl-(aq) –> AgCl(s)
What is the equation for the test for bromide ions?
Ag+(aq) + Br-(aq) –> AgBr(s)
What is the equation for the test for iodide ions?
Ag+(aq) + I-(aq) –> AgI(s)
How do you test for ammonium ions?
Add a few drops of sodium chloride to the solution then heat gently (1). If ammonium is present ammonia gas will be produced. To test for ammonia gas, hold a damp piece of red litmus paper near the gas and if it turns blue, then ammonia gas is present and therefore ammonium is present in the solution (1).
How do you do a precipitate test?
You add a few drops of sodium hydroxide to the solution and if a coloured precipitate forms then cations are present
What type of ions do flame tests, ammonium tests and precipitate tests test for?
Cations
What type of charge do cations have?
A positive charge
What type of ions to halide ion tests, carbonate tests and sulfate ions tests test for?
Anions
What type of charge do anions have?
A negative charge
What colour precipitate would Calcium ions form?
A white precipitate
What colour precipitate would copper ions form?
A blue precipitate
What colour precipitate would Iron(II) ions form?
A green precipitate
What colour precipitate would Iron(III) ions form?
A brown precipitate
What colour precipitate would Aluminium ions form?
A white precipitate that forms and then dissolves (as you add excess sodium hydroxide) into a colourless solution
