Chemical Analysis Flashcards
(32 cards)
How can you distinguish pure substances from mixtures?
Pure substances melt and boil at specific temperatures, impure substances melt at a range of temperatures
What is a formulation?
A mixture of substances in a fixed ratio designed for a specific purpose
Name some examples of formulations
Fuels
Cleaning products
Paints
Medicine
Fertiliser
What is the equation for calculating Rf value?
Distance moved by substance / Distance moved by solvent
Which substances move further up the filter paper and why?
More soluble substances
Because they have a greater attraction to the mobile phase
Which substances move less far up the filter paper and why?
Less soluble substances
They have a greater attraction to the stationary phase
Why is pencil used to draw the sample line?
Pencils are insoluble, meaning it won’t affect the results
What is the test for hydrogen?
Holding a lit splint and hearing a pop sound
What is the test for oxygen?
Relights a glowing splint
What is the test for carbon dioxide?
When bubbled through limewater (calcium hydroxide) the solution turns cloudy
What is the test for chlorine?
Bleaches damp litmus paper white
How do you carry out a flame test?
Dip a wire loop into the solution and hold it under a Bunsen burner
What colour does lithium burn?
Crimson
What colour does sodium burn?
Yellow
What colour does potassium burn?
Lilac
What colour does calcium burn?
Orange-red
What colour does copper burn?
Green
What is a precipitate?
An insoluble solid
Which metal ions form white precipitates when sodium hydroxide is added?
Aluminium
Calcium
Magnesium
Which metal ion forms a blue precipitate when sodium hydroxide is added?
Copper
Which metal ion forms a green precipitate when sodium hydroxide is added?
Iron (II)
Which metal ion forms a brown precipitate when sodium hydroxide is added?
Iron (III)
Which metal ion dissolves in excess sodium hydroxide solution?
Aluminium
What do carbonates produce when reacted with acids?
Carbon dioxide
