Paper Chromatography Flashcards
Chromatography
A method of separating mixtures of soluble substances
Mixture
Contains 2 or more substances not chemically combined
Solvent
a substance that dissolves a solute
Stationary phase
Is the paper in paper chromatography
Mobile phase
Is the solvent in paper chromatography
Chromatogram
Shows the results of separating the components of a mixture by chromatography
Pure substance
A substance that’s contains a single elements or compound not mixed with any other substance
Impure substance
Is made of more than one thing and produces two or more spots on a chromatogram
Rf value
A way of measuring how far a spot has travelled on a chromatogram compared to the distance the solvent has travelled
Solvent front
The furthest point the solvent travels in paper chromatography
Soluble
a substance that is dissolved in a solvent
Pencil line
Doesn’t dissolve in the solvent so can be used as a baseline to make measurements in paper chromatography
Which piece of equipment is used to measure time and are the units? [2]
Stopwatch in seconds
Which piece of equipment is used to measure temperature and what are the units? [2]
Thermometer in degrees celsius
Which piece of equipment is used to measure mass and what are the units? [2]
Mass balance in grams
Which 3 pieces of equipment are used to measure volume of a liquid and what are the units? [4]
measuring cylinder, volumetric pipette and burette in cm³
how to measure volume (gas) and unit
gas syringe in cm³
what process is used to separate two or more solids that are soluble [1]
paper chromatography
how do you calculate Rf value in paper chromatography? [1]
Distance moved by solute divided by distance moved by solvent
distance of solute/distance of solvent
Describe 3 ways that the purity of a substance can be assessed [3]
Melting point, boiling point, chromatography
Describe how melting point/ boiling point can be used to access purity [2]
A pure substance will have a sharp melting point / boiling point.
An impure substance will melt over a temperature change
Describe how chromatography can be used to assess purity [1]
A pure substance will produce only one well defined spot on a chromatogram
Describe two examples of where purity of substances is important [2]
manufacture of compounds used in drugs and food additives
solution
a liquid mixture
volatility
how easily a substance evaporates / changes from a liquid to a gas
solubility
how easily a substance dissolves
what is filtration used for? [1]
to separate a insoluble solid from a liquid
What is filtrate in filtration? [1]
the liquid or solution that has passed through the filter
What is crystallisation? [1]
the liquid that contains a dissolved salt is evaporated to leave the salt behind
What is distillation used for? [1]
to separate a solvent from a solution
What is the difference between immiscrible and miscible liquids? [2]
immiscibele liquids don’t mix, miscrible liquids do mix
how can immiscible liquids be separated? [1]
by using a separating funnel
