Chemical analysis Flashcards
What is a pure substance in chemistry?
Substance containing only one kind of element of compound, they melt/boil at specific temps
What is a pure substance in everyday life?
A substance to which nothing has been added
What is a formulation?
Mixtures prepared with a specific formula for a particular function
What is the process of chromatography used for?
To separate mixtures to identify substances
Describe the method of paper chromatography.
Draw pencil line 2cm above bottom of chromatography paper (baseline), add dot of ink on pencil line, put paper into a beaker with shallow amount of water (don’t submerge ink), cover with lid, wait for ink to travel up. Leave to dry.
How do we calculate Rf value?
Distance travelled by substance/ distance travelled by solvent
What is the mobile phase?
solvent in which the sample molecules can move, which in paper chromatography is liquid
What is the stationary phase?
Molecules in which the molecules can’t move, paper
What does the Rf value tell you?
The solubility
What is the test for chlorine?
Using a damp blue litmus paper, it should bleach white
What is the test for oxygen?
Glowing splint should relight
What is the test for hydrogen?
Lit splint should make a ‘squeaky pop’ noise
What is the test for carbon dioxide?
Lime water (calcium hydroxide) goes cloudy
