Summary Chemical Analysis

A mixture consists of two or more elements or compounds not chemically combined together:

 Homogeneous- mixture that is really well mixed (milk, blood, glue)
 Heterogeneous- mixture that is not really well mixed (pizza, fruit salad, tacos)

Mixture Compounds

- Variable composition – vary the amount of - Definite composition – can’t vary the amount
each substance in a mixture of each element in a compound

- Different substances are not chemically - Different elements chemically joined together
joined together
- The compound has properties which are
- Each substance in the mixture keeps its own different from the elements it contains
properties
- It can only be separated into its elements
- Each substance is easily separated from the using chemical reactions
mixture
- eg: Water, carbon dioxide,
- eg: Air and sea water
sodium chloride, calcium oxide



 Filtration- a mixture of water and an insoluble substance like sand can be separated by
filtering. The mixture of sand and water is poured into the filter funnel, which is lined with
filter paper. The water can pass through the paper to collect in the beaker. The sand
particles cannot pass through the filter paper and collect in the filter funnel.
 Crystallisation- is used to produce solid crystals from a solution. When the solution is
warmed, some of the solvent evaporates leaving behind a more concentrated solution. A
solution is placed in an evaporating basin and heated with a Bunsen burner. The volume of
the solution has decreased because some of the water has evaporated. Solid particles begin
to form in the basin. All the water has evaporated, leaving solid crystals behind.
 Simple Distillation- is used to separate a liquid from a solution. You put the solution in a flask
which is placed on top of a heating source (Bunsen burner), you then put a thermometer on
the top. The solution is heated and the part of solution with the lowest boiling point will
evaporate first. The vapour goes through the condenser which cools it and condenses it,
which is then collected in a beaker.
 Fractional Distillation- Fractional distillation is a method for separating a liquid from a
mixture of two or more liquids. For example, liquid ethanol can be separated from a mixture
of ethanol and water by fractional distillation. This method works because the liquids in the
mixture have different boiling points. When the mixture is heated, one liquid evaporates
before the other.
 Evaporation- by dissolving salt in water we make a solution. The salt disappears into the
water. We can separate the salt from the water by boiling the solution. The water will
evaporate until it is all gone. The salt will be left behind. If we collect the water vapour that
evaporates, we can cool it to form water again.
 Chromatography- A separation technique used to separate and or to analyse complex
mixtures. Draw a line with pencil near the bottom of the filter paper about 1cm thick. Add a
dot of ink in the middle of the line that you drew earlier. Hang the filter paper in the beaker
with water, using a rod or stick and paper clipping it together. Make sure that the water is
just slightly touching the bottom of the paper. The ink will slowly start to rise and separate