powder Magnesium Sulfate is colourless Copper(II) Oxide is black Bromine in solution is orange
Chapter 1 - States of Matter
The three states of matter: solids, liquids, gases
Arrangement of particles:
1) Solid- arranged regularly
and packed closely, they
vibrate about fixed
positions, and they have
strong forces of
attraction between them
2) Liquid- still mostly
touching but with some
gaps in between, they
move around each other,
and the forces of
attraction are weaker
than those in solids
3) Gas- move randomly at
high speeds in all
directions, they are further apart ,and there are almost no forces of attraction between them
Interconversions between the three states of matter
1) Solid-Liquid: melting and freezing at melting point
2) Liquid-Gas: boiling (at boiling point)/ evaporation (below boiling point only the particles on
the surface) and condensing
3) Solid-Gas: sublimation and deposition
4) When substances are heated, the particles absorb thermal energy which is converted into
kinetic energy. Heating a solid causes its particles to vibrate more and as the temperature
increases, they vibrate so much that the solid expands until the structure breaks and the solid
melts.
Diffusion: the random, net movement of particles in a fluid from an area of high concentration to an
area of low concentration until an equilibrium is reached
NH3(g) + HCl(g)-> NH4Cl(s)
White ring forms closer to the end of HCl
Solubility of Solids
,Solubility: the mass of a solute the mass of a solute which must dissolve in 100g of solvent to form a
saturated solution
1) Solute: substance that dissolves
2) Solvent: the liquid it dissolves in
3) Solution: the liquid formed
4) Saturated Solution: a solution which contains as much dissolved solid as possible at a
particular temperature
5) Solubility curve: a graph showing how the solubility of a solvent changes with temperature
Practical
Chapter 2- Elements, Compounds, and Mixtures
Element: a substance that cannot be split into anything simpler by chemical means, made up of only
one type of atom
,Compounds: two or more elements that have chemically combined (always in fixed proportions)
Mixture: two or more substances not chemically combined, which can be separated by physical
means
Pure substance: single element or compound; it has a sharp melting point
A student has two solids, X and Y.
One of these solids is a pure substance and the other is a mixture.
Describe how the student could identify which solid is pure and which is a mixture by measuring a
physical property of each solid
M1 measure the melting point
M2 if fixed/sharp melting point the substance is pure
M3 if melts over range of temperatures the substance is a mixture
Separation of Mixtures
1) Filtration: insoluble solid from a liquid, through filter paper (residue is called the substance
left behind and filtrate is the liquid that comes through)
A student is given 50 cm 3 of dilute sulfuric acid and a bottle of solid copper(II) carbonate.
Describe the method that the student should use to prepare a saturated solution of copper(II) sulfate.
In your answer, refer to the pieces of apparatus that the student should use.
M1 appropriate use of at least three named pieces of apparatus
AND any four of the following points
M2 add copper(II) carbonate to (dilute sulfuric) acid (a spatula/little at a time and stir after each
addition)
M3 until no more effervescence
ALLOW until no more reacts/dissolves
ALLOW until in excess
M4 filter (to remove excess copper(II) carbonate/to obtain (copper(II) sulfate) solution)
M5 heat/warm filtrate/(copper(II) sulfate) solution until crystals start to appear (solution saturated)
OWTTE
M6 filter to obtain (the saturated) solution
2) Crystallisation: solute from solution, heat the solution in an evaporating basin to boil off the
liquid until an almost saturated solution is formed, you then turn of the Bunsen burner and
separate the mixture through filtration (if you crush a rock and mix it with hot water the salt
will dissolve and the impurities can be filtered off)
, 3) Simple Distillation: The solution is heated, and pure water evaporates producing a vapour
which rises through the neck of the round bottomed flask. The vapour passes through the
condenser, where it cools and condenses, turning into the pure liquid that is collected in a
beaker. After all the water is evaporated from the solution, only the solid solute will be left
behind.
4) Fractional Distillation: This is used to separate two or more liquids that are miscible with one
another (e.g., ethanol and water from a mixture of the two). The solution is heated to the
temperature of the substance with the lowest boiling point. This substance will rise and
evaporate first, and vapours will pass through a condenser, where they cool and condense,
turning into a liquid that will be collected in a beaker. All of the substance is evaporated and
collected, leaving behind the other components(s) of the mixture. For water and ethanol
Ethanol has a boiling point of 78 ºC and water of 100 ºC. The mixture is heated until it
reaches 78 ºC, at which point the ethanol boils and distills out of the mixture and condenses
into the beaker. When the temperature starts to increase to 100 ºC heating should be stopped.
Water and ethanol are now separated
5) Paper Chromatography: