Testing for Ions

Question 1

What is meant by the term malleable?

Answer 1

Bent/changed into shape

Question 2

Explain in Terms of it’s structure why magnesium is Malleable?

Answer 2

-layers or atoms can slide over each other

Question 3

state one industrial use for diamond?

Answer 3

Diamond drill bits

Question 4

Diamond and graphite both have high melting points explain why?

Answer 4

• stron cobalent bonds

- require lots of energy to break

Question 5

Fe2+
Fe3+
Cu2+
Li+
Na+
K+
Ca2+
Name these common ions

Answer 5

Iron 2+
Iron 3+
Copper2+
Lithium
calcium
potassium
Calcium2+

Question 6

Iron(II) solution with sodium hydroxide forms a

Answer 6

gelatinous green precipitate

Question 7

Iron (III) solution with sodium hydroxide forms a

Answer 7

brown precipitate

Question 8

Copper(II) with sodium hydroxide forms a

Answer 8

blue precipitate

Question 9

Lithium produces what colour flame in the flame test?

Answer 9

Red

Question 10

Pottasium in the flame test

Answer 10

lilac

Question 11

sodium in the flame test

Answer 11

yellow

Question 12

calcium in the flame test

Answer 12

brick red

Question 13

Test for aninon: add hydrochloric acid what happens

Answer 13

carbonate gives off effervescence

-gas turns limewater milky-CO2

Question 14

Name the three halide ions

Answer 14

chloride
bromide
iodide

Question 15

add nitric acid +silver nitrate solution to chloride-

Answer 15

forms a white precipitate

Question 16

add nitric acid and silver nitrate solution to bromide

Answer 16

cream precipitate with silver nitrate

Question 17

add nitric acid and silver nitrate

Answer 17

yellow precipitate with silver nitrate

Question 18

add hydrochloric acid and barium chloride solutions

Answer 18

sulphates give white precipitates or barium sulphate

Question 19

What must be used for a flame test wire?

Answer 19

inert metal

Question 20

method for the flame test?

Answer 20

• dip the wire into the test substance

- place the wire and the test substance on the side of a roaring flame or (non luminous) bunsen flame

Question 21

Hydroxide precipitate test method

Answer 21

• place 1cm cubed of test solution into test tube if given a substance as a solid it must first be dissolved in water to make a solution
• add drop by drop sodium or (potassium) hydroxide solution and mix gently
• record observations

Question 22

What are three ionic compounds that contain ammonium

Answer 22

Ammonium Chloride
Ammonium hydroxide
ammonium sulphate

Question 23

Method to test compound containing ammonium

Answer 23

• add a few CM3 of sodium hydroxide solution
• gently warm test tube
• hold a piece of damp red litmus paper at the mouth of the test tube
• If ammonia gas is released red litmus turns blue

Question 24

What happens if test compound contains ammonium ions

Answer 24

ammonia gas is released

Question 25

why do we use distilled water when making a solution

Answer 25

distilled water doesn’t contain other ions

Question 26

when testing for sulphate ions why use dilute hydrochloric acid?

Answer 26

to remove other ions that can form a precipitate with barium chloride solution

Question 27

what is the word equation for barium and copper sulphate

Answer 27

Copper sulphate + Barium Chloride > barium sulphate (white ppt) + copper chloride