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Topic 3 ­ covalent compounds and separation techniques

Covalent compounds

A covalent bond is formed between non-metal atoms which
combine together by sharing electrons. The shared pair of electrons
holds the two atoms together and this is called a covalent bond.
Atoms bonded together in this way are called molecules.…

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Dot and cross models

Molecule Dot and cross model

Hydrogen (H2)


Chlorine (Cl2)



Methane (CH4)




Water (H2O)



Carbon dioxide (CO2)


Oxygen (O2)



Hydrogen chloride
(HCI)




Covalent compounds have low melting and boiling points because
they have weak intermolecular forces even though the covalent
bonds binding the atoms are very strong.…

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Simple molecular compounds

Properties:

Low melting and boiling points ­ weak intermolecular forces
Non-conductive ­ no free electron or an overall electrical
charge

Hydrogen, ammonia, carbon dioxide, methane and water are simple
molecules with covalent bonds. They all have strong bonds between
atoms but weak intermolecular forces between molecules. When…

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semi-conductive which means it is between non-conductive
and conductive.

Graphite

Graphite is an allotrope of carbon, so formed by carbon atoms
but in layers. These layers can slide over each other due to the
weak forces between layers therefore graphite is much more
softer than diamond. This means that graphite…

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The fact that diamond has 4 strong covalent bonds means that
there are no free electrons and ions. This is why diamond does
not conduct electricity. Also diamond is insoluble in water.

Buckminsterfullerene

It is an allotrope of carbon and it's a type of fullerene which
are carbon atoms joined…

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Separation of liquids:

Immiscible liquids mean that liquids do not dissolve in each
other e.g. oil and water. A separating funnel is used to
separate immiscible liquids by waiting until two layers form
(denser liquid (water) sinks to the bottom and the less denser
one (oil) forms a layer at…

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Chromatography

It is used to separate mixtures of colour compounds. These include
ink, dyes and food colouring.

A spot of the mixture is placed on a paper with a pencil (doesn't mix
with mixture) on the baseline of the paper. The paper is then
placed upright in a beaker containing…

Comments

Mist

Hi, do you have any c1 chemistry core notes ???

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