C3 Flashcards
How do you calculate the Rf value?
Rf= Distance substance has travelled /
distance solvent has travelled
What is a mixture?
A substance with more than one type of particle that is not chemically joined.
Heating curves for pure and impure substances?
Pure ones are very straight whereas the impure ones are not horizontal at the melting point because there are different substances within it which have different melting points.
Describe the moment of the particles in the 3 states of matter…
SOILD vibrates in a fixed position
LIQUID rolling over each other
GAS flying around with high energy
Describe filtering and crystallisation in a mixture of sand and salt…
Make a salt solution by dissolving the salt in the solvent(water)
Then filter the filtrate from the residue.
Then evaporate the solvent from the filtrate to get crystals of the solute.
How do you separate a solvent and a solute?
Evaporation (to keep solute)
Distillation (to keep solvent)
What is distillation?
When a mixture is boiled and a solvent is evaporated then condensed in order to separate it from something.
What are the risks in distillation?
Bunsen = leave on safety flame Flask= Add anti bumping granules for no spillage Fumes= Use condenser
How would the chromatogram of a pure and impure substance be different?
A pure substance has one dot, an impure has multiple.
Define: Course filtration Sedimentation Fine filtration Chlorination
Course filtration:Removes sticks, leaves…
Sedimentation:chemicals are added particles stick together + sink
Fine filtration: water passed through sand insoluble particles are removed
Chlorination:A small amount of chlorine gas is added to kill microbes.
How does using a condenser improve simple distillation?
Improves condensing of the solvent and makes distillation safer.
How can the chromatogram of a known substance, be used to identify unknown substance?
Rf values will be the same for the same substances.
