to determine the density of water, ethanol and hexane
to determine the melting point of an unknown compound
and then use this melting point as an aid in its identification. The unknown
compound will be one of the following:
Acetanilide (m.p. = 113 -115oC)
Benzoic acid (m.p. = 122oC)
Cinnamic acid (m.p. = 133oC)
Adipic acid (m.p. = 152oC)
Salicylic acid (m.p. = 159oC)
to compare the solubility of various solid substances
in water and in hexane. Various liquids will also be mixed to determine which
combinations are miscible and immiscible.
is a physical property which can be used to identify substances. Density is
defined as the mass per unit of volume
Density = mass/volume
Mass is a measure of the quantity of matter contained in
an object. Volume is a measure of the space occupied by an object.
The melting point and boiling point of a substance are also
characteristic physical properties, which can be used to identify a substance.
The melting point is defined as the temperature at which the liquid and solid
phase of a substance co-exist at equilibrium. Pure compounds melt at a sharp
temperature. Impure compounds melt at a lower temperature and over a wider temperature
range. The boiling point of a substance depends on the air pressure. The greater
the air pressure the higher the boiling point.
has two components, a solute and solvent. When sugar dissolves in water the
sugar is the solute and the water is the solvent. Whether a solute dissolves
in a solvent to form a solution depends on the nature of the solute and solvent.
Substances which dissolve in water (e.g. sugar) are described as being soluble
while other substances (e.g. sand), which do not dissolve in water are described
If two liquids are soluble in each other (e.g. alcohol and
water) they are described as being miscible. Two liquids, which are insoluble
in each other (e.g. oil and water) are said to be immiscible.