Chemical Analysis Flashcards
What are some separation techniques?
Filtration
Evaporation
Crystallisation
Simple distillation
Fractional distillation
Chromatography
What apparatus does a filtration use?
Check notes for diagram.
Filter paper
Filter funnel
Clamp
Beaker
Tile
What does a filtration separate?
Insoluble substance from liquid.
What apparatus does evaporation use?
Check notes for diagram
Evaporating basin
Gauze
Bunsen burner
Tripod
Heatproof mat
What is evaporation used to separate?
Separates a solute from a solvent e.g. salt from salt water.
What apparatus does simple distillation use?
Check notes for diagram
Borrorned flask
Lietig condenser
Tripod stand
Wire gauze
Bunsen burner
Beaker
What is simple distillation used to separate?
Solvent from a solution
What is the substance collected from a distillation called?
distillate
What apparatus does fractional distillation use? (lab method)
Bunsen burner
Flask
Fractioning column
Thermometer
Condenser
Beaker
What is fractional distillation used to separate?
2 or more miscible liquids.
What apparatus does chromatography use?
Filter paper
Pencil
Beaker
Solvent
What is chromatography used to separate?
2 or more substances in a solution
What is the mobile phase in chromatography?
Phase that moves.
How do you calculate Rf?
Distance moved by sample
—————————————
Distance moved by solvent
What is potable water?
Water safe to drink
What is desalination?
The process of removing dissolved substances from sea water.
What is the test for water?
Add to anhydrous copper(II) sulfate crystals
Changes white to blue
What is a precipitate?
A solid which may be formed in mixing two solutions.
What is the test for chlorine?
Turns universal indicator paper red then white
How do you test for cations?
Add approximately 5 cm3 of the solution to be tested to a test-tube.
Add sodium hydroxide solution slowly drop wise.
Note your observations in the table.
Continue adding sodium hydroxide drop wise to any precipitates until a large excess is present (about 2/3 full).
Stopper and shake the test tube thoroughly.
Note your observations
How do the melting and boiling points of pure substances and mixtures differ?
Pure substances give a sharp boiling and melting point.
Impure substances give boiling and melting points over a range, as the different substances they contain have different points.
The greater the amount of an impurity the greater the difference from the true melting/boiling point and the higher the range.
How does the presence of an impurity affect the melting/ boiling point of a solid vs Liquid?
Lowers point of solid.
Raises point of liquid.
