Tests Flashcards Preview

Chemistry spec > Tests > Flashcards

Flashcards in Tests Deck (24)
Loading flashcards...
1
Q

flame test method

A
  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
2
Q

lithium flame goes

A

red

3
Q

sodium flame goes

A

orange

4
Q

potassium flame goes

A

lilac

5
Q

calcium flame goes

A

brick red

6
Q

testing for ammonium (NH4+ ions)

A

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

7
Q

equation for testing for ammonium ions

A

NH4+ + OH- goes to NH3 + H20

8
Q

how to recognise ammoia

A

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

9
Q

precipitation reactions- transition metals

A

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

10
Q

Cu2+ produces the precipitate

A

copper hydroxide (light blue)

11
Q

fe2+ produces the precipitate

A

Iron (II) hydroxide (green)

12
Q

Fe3+ produces the precipitate

A

Iron (III) hydroxide (red/brown)

13
Q

precipitation reaction equations

A

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

14
Q

test for halides

A

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

15
Q

chloride halide test

A

white precipitate- silver chloride

16
Q

bromide halide test

A

cream precipitate- silver bromide

17
Q

iodide halide test

A

yellow precipitate- silver iodide

18
Q

testing for sulphate ions

A

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

19
Q

testing for carbonate ions

A

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

20
Q

gas test for chloride

A

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

21
Q

oxygen gas test

A

relights a glowing wooden splint

22
Q

carbon dioxide gas test

A

turns limewater (calcium hydroxide solution) cloudy

23
Q

hydrogen gas test

A

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

24
Q

ammonia gas test

A

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