chemical analysis

what flame colour is copper?

green

what flame colour is lithium?

crimson red

what flame colour is potassium?

lilac

what flame colour is sodium?

yellow

what flame colour is calcium?

orange red

what colour precipitate does copper turn in sodium hydroxide?

blue

what colour precipitate does iron ii form in sodium hydroxide?

dirty green

what colour precipitate does iron iii form in sodium hydroxide?

brown

which anions form a white precipitate in sodium hydroxide?

al3+, ca2+, mg2+

which anion turns the sodium hydroxide colourless when it’s added in excess?

al3+

write a balanced symbol equation between the aluminium anion and hydroxide cation?

al3+ + 3OH- —→ al(OH)3

what test is done to test for carbon ions?

add a dilute acid, if fizzing occurs, carbon is present

(remember acid reactions:acid+carbonate—> co2 + h2o +salt

acid+alkali reaction

salt and water

metal+acid reaction

salt and hydrogen

carbonate+acid reaction

CO2, water and salt

acid+ metal oxide reaction

salt and water

what is the test for sulfate ions?

what is the positive result?

add barium chloride solution (ba2+) and hydrochloric acid, white precipitate forms

test for halide ions?

add silver nitrate and dilute nitric acid solutions, precipitate with turn different colours

what is the result for iodides using the halide test?

forms a yellow precipitate

iodide test equation

I- + Ag+ —> AgI

Chloride test result using halide test

white precipitate

chloride test equation

Cl- + Ag+ —> AgCl

Bromine result using halide test

Cream precipitate

bromine test equation

Br- + Ag+ —> AgBr

what are some advantages of using flame emission spectroscopy? (3)

-can see concentrations of the metal ion (lots of information)

-allows for a definite answer (sometimes hard to distinguish between colours using normal flame)

-fast and accurate

what are some disadvantages to normal flame tests? (2)

-inaccurate if samples are contaminated

-uses up sample