What is a solvent?
The liquid which a solute is dissolved into
What is a solute?
The soluble solid being dissolved in the solvent
What is a solution?
A solute dissolved in a solvent
What is a saturated solution?
A solution where no more solute can be dissolved, leaving sediment
What is an element?
One type of atom
What is a compound?
Two or more atoms, chemically bound together
What is a mixture?
Two or more substances mixed together, but not chemically bonded
What is the solubility equation?
Solubility = mass of solute (g) ➗ mass of solvent removed ✖️100
What is the difference between pure substances and mixtures?
pure substances have a fixed melting or boiling point, mixtures melt or boil over a range of temperatures.
How would you investigate solubility at different temperatures?
- Add 20ml water to a boiling tube and measure the temp. of the water. Let the water cool to the temp. you want to work at.
- Add the solute until saturated then filter this
- Record the mass of the evaporating basin
- Put into this the filtrate, then evaporate this.
- Record the mass of the evaporating basin and solute.
- From this work out the solubility and compare to the solubility at different temperatures
What are the 5 ways to separate mixtures?
Crystallisation, Simple Distillation, Fractional Distillation, Paper Chromatography and Filtration
What is Simple Distillation used for?
To separate a liquid or solid from a solution, if we want to keep the liquid
How do you do Simple Distillation?
- Heat the solution. The part of the solution with the lowest boiling point evaporates
- This vapour is condensed in the condenser and then collected in a beaker
- The rest of the solution is left behind in the flask
What is Fractional Distillation used for?
To separate a mixture of liquids
How do you do Fractional Distillation?
- Put the mixture into a flask and put ontop a fractionating column
- Heat this and, because different liquids have different boiling points, they will evaporate at different temperatures.
- The liquid with the lowest boiling point will evaporate first. When the temp. on the thermometer reads the boiling point of this liquid, it will reach the top of the column
- Liquids with higher boiling points may also start to evaporate, but will condense and drip back into the flask
- When the liquid has been condensed and collected, turn up the heat to collect the next liquid
What is Crystallisation used for?
To separate a soluble solid from a solution
How do you do Crystallisation?
- Put the solution into a evaporating basin and heat
- The liquid will evaporate. When you start to see crystals forming, remove the dish from the heat and leave it to cool.
- The solid should start to become insoluble in the cold, highly saturated solution
What is Filtration used for?
To separate an insoluble solid from a liquid
How do you do filtration?
- Put folded filter paper on top of a filter funnel and put in the mixture
- The mixture will drip through into the beaker, leaving behind the solid
What is paper chromatography used for?
To separate dyes in inks
What is the stationary phase is paper chromatography?
The chromatography paper
What is the mobile phase in paper chromatography?
The inks travelling up the paper
Why is the baseline drawn in pencil in paper chromatography?
Pencil marks are insoluble and won’t dissolve in the solvent
What is the solvent front?
The line on the paper where the solvent stops
