Tests

Question 1

flame test method

Answer 1

1. clean a platinum wire loop by dipping it in some dilute HCL then holding it in a flame and then dip it in the sample solution
2. hold the flame test loop at the edge of the bunsen burner flame
3. observe the changed colour of the flame and then decide which metal it indicated
4. clean the loop in acid and rinse it with water, then repeat with a new sample

Question 2

lithium flame goes

Answer 2

red

Question 3

sodium flame goes

Answer 3

orange

Question 4

potassium flame goes

Answer 4

lilac

Question 5

calcium flame goes

Answer 5

brick red

Question 6

testing for ammonium (NH4+ ions)

Answer 6

sodium hydroxide solution is added to the test solution and gently heated. If ammonium ions are present, then ammonia gas will be given off.

Question 7

equation for testing for ammonium ions

Answer 7

NH4+ + OH- goes to NH3 + H20

Question 8

how to recognise ammoia

Answer 8

it has a sharp, choking smell , it makes dampp red litmus turn blue

Question 9

precipitation reactions- transition metals

Answer 9

if a solution of any soluble transition metal is mixed with sodium hydroxide solution, then a displacement reaction occurs. he sodium is the more reactive metal and displaces the transition metal from its compound. This produces a precipitate

Question 10

Cu2+ produces the precipitate

Answer 10

copper hydroxide (light blue)

Question 11

fe2+ produces the precipitate

Answer 11

Iron (II) hydroxide (green)

Question 12

Fe3+ produces the precipitate

Answer 12

Iron (III) hydroxide (red/brown)

Question 13

precipitation reaction equations

Answer 13

Cu2 + + 2OH- goes to Cu(OH)2
Fe2+ Fe
Fe3+ 3 Fe 3

Question 14

test for halides

Answer 14

Add dilute nitric acid (HN03) followed by silver nitrate solution (AgNO3)

Question 15

chloride halide test

Answer 15

white precipitate- silver chloride

Question 16

bromide halide test

Answer 16

cream precipitate- silver bromide

Question 17

iodide halide test

Answer 17

yellow precipitate- silver iodide

Question 18

testing for sulphate ions

Answer 18

add dilute HCL followed by barium chloride solution (BaCl2) a white precipitate of barium sulphate forms if sulphate ions are present.

Question 19

testing for carbonate ions

Answer 19

add dilute hcl to your test sample, if carbonates are present then co2 will be released

Question 20

gas test for chloride

Answer 20

bleaches damp litmus paper turning it red primarily and then bleaching it white

Question 21

oxygen gas test

Answer 21

relights a glowing wooden splint

Question 22

carbon dioxide gas test

Answer 22

turns limewater (calcium hydroxide solution) cloudy

Question 23

hydrogen gas test

Answer 23

makes a squeaky pop when lighted wooden splint is in a test tube of hydrogen

Question 24

ammonia gas test

Answer 24

turns damp red litmus paper blue (also has a very strong smell)