Analysing Substances

Question 1

lithium burns what colour?

Answer 1

Crimson

Question 2

Sodium burns what colour?

Answer 2

Yellow

Question 3

Potassium burns what colour?

Answer 3

Lilac

Question 4

Calcium burns what colour?

Answer 4

Brick red

Question 5

Barium burns what colour?

Answer 5

Green

Question 6

if you add sodium hydroxide to an unknown solution in a test for positive ions and you get a white precipitate, what would that mean if it dissolves?

Answer 6

it’s Al3+

Question 7

if you add sodium hydroxide to an unknown solution in a test for positive ions and you get a white precipitate, if it doesn’t dissolve in excess?

Answer 7

if you burn it and it burns red then it’s Ca2+

Question 8

if you add sodium hydroxide to an unknown solution in a test for positive ions and you get a coloured precipitate then what colour means what ion?

Answer 8

brown = Fe3+
Green = Fe2+
Blue = Cu2+

Question 9

the test for carbonates

Answer 9

adding dilute acids, should fizz if carbon dioxide is present.

Question 10

test for lime water

Answer 10

Co2, makes a white precipitate and makes limewater cloudy.

Question 11

test for halides?

Answer 11

• add dilute nitric acid
• silver nitrate solution
• precipitate is formed

Question 12

during the test for halides, what do the different coloured precipitates mean?

Answer 12

• white = silver chloride
• cream = Silver bromide
• yellow = Silver iodide

Question 13

test for sulfates consist of?

Answer 13

• add dilute acid
• add barium chloride solution
• white precipitate formed if sulfate ions are present