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1) Mass of sugar and flavourings
present = mass of crucible - mass of crucible when all the water has evaporated.
Mass of sugar and flavourings per ml = (answer to 1) above) / 5mls
Percent of sugar by mass = (mass of sugar/mass of lemonade)X100
Below is an example of the calculations
Mass
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Mass of crucible |
23.40g
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Mass of crucible and 5mls of lemonade |
30.14g
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Mass of crucible when all the water has evaporated |
25.14g
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Mass of sugar and flavourings present |
25.14g
- 23.40g=1.74g
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Mass of sugar and flavourings per ml |
1.74g/5mls
=0.35g/ml
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Percentage of sugar by mass |
mass of lemonade = 30.14-23.40 = 6.74g (0.35/6.74)X100 = 5.28% |
Separating mixtures
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Lemonade is
a mixture of different compounds. Carbon dioxide, water and sugar are
the major ingredients. Separating the carbon dioxide from the lemonade
is easy. Sometimes it just requires a little shaking and the lemonade
soon becomes flat. Lemondae is said to be flat when all the carbon dioxide,
that gives it the fizz, is gone.
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To
separate the water and the sugar is going to be a little more difficult.
Stephen suggested that filtering the lemonade through fine filter paper
will separate the sugar form the water. Is this possible? Explain . What happens to soluble substances, like sugar or salt, when they dissolve in water? |
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Weigh a clean crucible. Using a measuring cylinder, measure 5mls of lemonade and place this volume in a crucible. Weigh the crucible and its contents. Heat the crucible to evaporate the water as shown on the right. | |||||||||||||||
When
most of the water has evaporated remove the crucible from the flame and
allow it to sit. The mixture is very hot and the water is still evaporating.
Smell the contents of the crucible. Is the smell familiar? What do you think is the major component of the mixture left behind? |
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Weigh the crucible when it
has cooled down and fill in the table below.
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Try
this experiment with other brands of soft drink and determine which one
has the most sugar content per ml of drink. How does diet lemonade differ from normal lemonade? |
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