Unit 25 & 26 - Qualitative Analysis: Tests For Ions/ Bulk And Surface Properties Of Matter Inclusing Nanoparticles Flashcards
How do you carry out a flame test
Light a Bunsen burner and give it a blue flame
Pick up a small sample using a wire loop
Hold at the edge of the flame and observe the flame colour
What must you do to the wire loop before testing each flame sample
Clean it using hydrochloric acid
What metal might be used as the wire loop and why (2)
Platinum because it’s very unreactive and has a high melting point
Nichrome because it’s cheaper and produces a faint orange colour
What colour does the flame turn with Li+
Red
What colour does the flame turn with Na+
Yellow
What colour does the flame turn with K+
Lilac
What colour does the flame turn with Ca2+
Orange-red
What colour does the flame turn with copper Cu2+
Blue-green
What is a flame photometer
A machine that measures the light intensity of the flame colours
Why is flame photometry better than flame tests? (3)
More sensitive, more accurate, faster
What is a standard solution
A solution containing precisely known measurements of substances
Give a way of treating contaminated water with drains from mines
Using sodium hydroxide solution
What do sodium hydroxide precipitation reactions involve
Adding it to a test to identify dissolved metal ions
When Fe2+ is added to sodium hydroxide, what colour is the precipitate?
Green
When Fe3+ is added to sodium hydroxide, what colour is the precipitate?
Brown
When Cu2+ is added to sodium hydroxide, what colour is the precipitate?
Blue
When Ca2+ is added to sodium hydroxide, what colour is the precipitate?
White
When Al3+ is added to sodium hydroxide, what colour is the precipitate?
White
How can you distinguish calcium ions and aluminium ions if they both form white precipitates?
Aluminium hydroxide disappears to form a colourless solution when excess sodium hydroxide is added but calcium hydroxide doesn’t
What is the tests for ammonia ions
Ammonia changes damp red litmus paper blue
What do rocks with carbonate minerals produce when added to HCl
Bubbles of CO2
What is the tests for carbonate ions
Adding HCl makes CO2
What is the test for sulphate ions
Add HCl to acidity solution and remove carbonate ions, add some barium chloride, if sulphate is present, a white precipitate forms
What is the precipitate formed when barium chloride is added to sulphate ions
Barium sulphate
Which is the only silver halide that is soluble in water
Silver fluoride
How do you detect chloride, bromide and iodide ions?
Add nitric acid to acidity solution and remove carbonate ions, then add silver nitrate which will change the colour