Paper 2: Chemical analysis Flashcards
What is a pure substance?
A single element or compound
What is a formulation?
A mixture that has been designed as a useful product
Examples of formulations
Fertilisers, fuels
Describe paper chromatography
-Draw a start line in paper at the bottom of the paper and spot on the mixture
-Fill beaker with solvent, not above the start line
-Hang paper on rod and place in beaker
-Solvent travels up paper separating the components
-Take paper out when solvent reaches the end
How do you calculate Rf value?
Distance moved by spot/distance moved by solvent
Stationary phase
The paper
Mobile phase
The solvent
Test for hydrogen
Pop with a burning splint over gas
Test for Oxygen
Glowing splint relights
Test for Carbon dioxide
Turns limewater milky
Test for Chlorine
Bleaches damp litmus paper and makes it white
What is Rf value?
Ratio between distance traveled by solute and distance traveled by solvent
How do you use chromatography to see if a certain substance is in a mixture?
-Run a pure sample of substance alongside unknown sample and if the Rf value matches of one of spots from the mixture it is present
Why should pencil be used to draw the line along the bottom of chromatography paper
Insouble in solvent so wont effect experiment
2 factors that affect how long molecules spend in each phase in chromatography
-solubility
-How much attracted to the paper
