4.6 - Chemical Analysis

Question 1

Chemical test for water

Answer 1

anhydrous copper sulfate

Question 2

Chemical test for water: COLOUR CHANGE

Answer 2

white to blue

Question 3

Purity of water

Answer 3

boiling point - 100C

Question 4

Test for chlorine

Answer 4

damp blue litmus paper

Question 5

Test for chlorine: COLOUR CHANGE

Answer 5

blue to white (bleached)

Question 6

Test for ammonia

Answer 6

damp red litmus paper

Question 7

Test for ammonia: COLOUR CHANGE

Answer 7

red to blue

Question 8

What cations do you test for in the flame test?

Answer 8

-lithium
-sodium
-potassium
-calcium
-copper

Question 9

Flame test: what type of wire do you use?

Answer 9

nichrome/ platinum wire

Question 10

Flame test: what acid do you initially dip the nichrome wire in to?

Answer 10

hydrochloric acid

Question 11

Flame test: what type of flame do you put the tip of the wire in?

Answer 11

non-luminous Bunsen flame

Question 12

Flame test colour: lithium

Answer 12

red

Question 13

Flame test colour: sodium

Answer 13

yellow

Question 14

Flame test colour: potassium

Answer 14

purple

Question 15

Flame test colour: calcium

Answer 15

orange-red

Question 16

Flame test colour: copper

Answer 16

blue-green

Question 17

What cations do you test for in the sodium hydroxide test?

Answer 17

-copper
-iron II
-iron III

Question 18

Sodium hydroxide test: How do you conduct it?

Answer 18

-dissolve sample in water
-add few drops of NaOH

Question 19

Sodium hydroxide test: copper

Answer 19

blue precipitate

Question 20

Sodium hydroxide test: iron II

Answer 20

green precipitate

Question 21

Sodium hydroxide test: iron III

Answer 21

brown precipitate

Question 22

Ammonium test: How do you conduct it?

Answer 22

-dissolve sample in water
-add some NaOH and warm it
-test gas evolved with red litmus paper

Question 23

Silver nitrate test: what anions does it test for?

Answer 23

halide ions
-bromine
-chlorine
-iodine

Question 24

Silver nitrate test: How do you conduct it?

Answer 24

-dissolve sample in water
-add nitric acid (HNO3)
-add silver nitrate (AgNO3)

Question 25

Silver nitrate test: chlorine

Answer 25

white precipitate

Question 26

Silver nitrate test: bromine

Answer 26

cream precipitate

Question 27

Silver nitrate test: iodine

Answer 27

yellow precipitate

Question 28

Test for carbonates: How do you conduct it?

Answer 28

-add HCl and look for effervescence -if there is effervescence then bubble through limewater

Question 29

Test for carbonates: colour change

Answer 29

limewater turns cloudy

Question 30

Test for sulfates: How do you conduct it?

Answer 30

-add HCl and look for effervescence -if there is no effervescence then add barium chloride solution

Question 31

Test for sulfates: observations

Answer 31

white precipitate forms (if positive)