Download chemical reactions

Forrester High School: Chemistry Summary notes
1a) CHEMICAL REACTIONS
In a CHEMICAL REACTION, new substance/s are formed.
Some ways of telling if a chemical reaction has occurred are:
i) Change in appearance:

The colour may change.

A precipitate (solid) formed when two solutions are mixed.

Effervescence (bubbles of gas).
ii) Change in energy:

Heat may be given out.
It gets hot.

Heat may be taken in.
It gets cold. (Endothermic)

Light may be given out.

Sound may be produced (e.g. explosions, fizzing).
Topic 1 Chemical Reactions
(Exothermic)
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Forrester High School: Chemistry Summary notes
1b)Elements mixtures & Compounds
ATOMS AND ELEMENTS
An ATOM is the smallest particle from which substances are made.
In an ELEMENT, all the atoms are the same.
Only about 110 different kinds of atoms known. There are therefore are110
different elements, each with their own symbol.
When different elements react, their atoms join to make a compound, thus
compounds contain different atoms joined together
A COMPOUND is made of atoms of two or more different elements, chemically
joined.
MIXTURES consists of two or more substances which are simply mixed, but not
chemically joined.
Mixture of
element & compound
Topic 1 Chemical Reactions
mixture of
two compounds
mixture of
2 different element
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Forrester High School: Chemistry Summary notes
Separating Mixtures:
a) to separate two liquids mixed together
distillation
chromatography
Solvent front
Spots
X
Solvent
b) to separate a solid mixed with a liquid filtration
Filter Funnel
Filter paper
Residue (un-dissolved solid)
Filtrate
c) to separate a dissolved solid from the solvent
solvent evaporating
HEAT
d)
Separate two solids mixed together dissolving then:
filter if one is insoluble or distil if both are soluble.
Topic 1 Chemical Reactions
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Forrester High School: Chemistry Summary notes
SOLUTIONS
A SOLUTE:
a substance which is being dissolved.
Solid solute
A SOLVENT:
a liquid in which something dissolves.
A SOLUTION:
made by dissolving a SOLUTE in a SOLVENT.
A SATURATED solution is when so much solute has been added that no more
can dissolve.
Topic 1 Chemical Reactions
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