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In 8 AD, Augustus Caesar exiled the Roman poet Ovid
(Publius Ovidius Nasso 43 B.C.-17 AD) to the remote Black Sea town of Tomis
(modern Constanta, Romania). Not
only was Ovid isolated from the political, social and intellectual center
of his world, but he also had to endure a climate much harsher than that of
Rome. To lament his exile, he wrote
the Tristia, poems that detail his physical and emotional discomforts.
Our modern day temperature scales can be traced back to no earlier than the
17th century; therefore no temperature records from the Ovid's time
exist. However, chemistry students will immediately recognize that
the phenomenon of freezing point depression can be applied to estimate the
temperature of Tomis in the year 8 AD, provided that the composition of the
wine can be accurately estimated.
Throughout the Roman Empire, there were many kinds of wine consumed,
some of which were diluted with water.
However, the exact Latin words used by Ovid to describe the wine he
writes about were "vina" and "meri". These words were used to describe undiluted
wines.
Read the poem from Tristia by Ovid you were given. Underline passages related to climate
and temperature.
Obtain 25.0 ml of "sweet" wine and 25.0 ml of "dry"
wine, each in a 50 ml beaker. Place
both in a container filled with an ice/water/rock salt mixture which is
cooled to about -10.0 degrees Celsius.
With occasional stirring, freeze both wines, recording the temperatures
where ice crystals are first seen.
The temperatures should hold steady at the freezing points. If ice does not form by about -10.0
degrees Celsius, see your instructor for suggestions to prevent supercooling.
From the information on the labels, calculate the expected freezing points
of each wine, using the freezing point constant of water, the density of
ethanol, the density of water, and the alcohol content of the wine. Then from the difference between the
calculated freezing points and observed freezing points, calculate the
molarity and mass percent of sugar in each wine. A difference is expected because the calculations assumed the
only chemical causing the freezing point to decrease is the alcohol.
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