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Part I: Density of a Liquid
You will measure the density of the same liquid three times to demonstrate the difference
in various techniques for measuring the volume. In a clean, dry beaker of an appropriate size, get
approximately 30 ml of the unknown liquid and bring it to your desk. Get the dry weight of a
second clean and dry container. Using a pipette, put 20.00 ml of the unknown liquid into the
second beaker. Determine the mass of the second beaker with the liquid in it. Dakota State University Page 48 of 232 Experiment 1: Density of a Liquid and a Solid General Chemistry I and II Lab Manual Return the liquid to the first beaker, and dry the second beaker. Using a clean and dry
graduated cylinder, measure out 20.0 ml of the unknown liquid and put it into the second beaker.
Again, get the mass of the second beaker with the liquid in it.
Once again, return the unknown liquid to the original beaker. Measure out 20. ml of the
unknown liquid using an Erlenmeyer flask. Determine the mass of the beaker with the liquid in
Dispose of the unknown liquid as instructed.
Part II: Density of an Unknown Solid
From time to time, a chemist has to be clever enough to find an indirect method to
measure some quantity. For example, how would one go about measuring the volume of an
unusually shaped solid. Archimedes faced this problem when be had to determine the density of
a crown for the king in order to determine whether or not the blacksmith stole some of gold and
substituted copper for it. To do so, he used water displacement to determine the volume of the
crown, as you will do for this part of the experiment.
Get a solid object from your instructor. Determine At mass on an electronic balance.
Choose a graduated cylinder of an appropriate size. Fill it approximately half full with water. It is
not important to fill it to exactly half, but it is important to determine exactly what the initial
volume is. Once you have recorded the volume, carefully lower the solid into the graduated
cylinder so as to avoid splashing the water or breaking the graduated cylinder. Once you have
recorded the final volume, dry the solid and return it.
Part III: The volume of a grain of sand
Now let’s try our hands at critical thinking and experimental design. I have a very simple
question for you; what is the average volume of one grain of sand? Talk with your lab partners
and come up with a few approaches to answering this problem. Then, discuss each procedure in
turn, critically analyzing it for weaknesses and difficulties. Decide upon a best procedure and
give it a try. You will be graded on accuracy.
For each of the three trials, determine the mass of the liquid by subtracting the mass of
the container from the mass of the container and liquid. Divide the mass of the liquid by the
volume (20 mL) to determine the density.
Part II: Dakota State University Page 49 of 232 Experiment 1: Density of a Liquid and a Solid General Chemistry I and II Lab Manual To determine the volume of the object, subtract the volume of the liquid in the graduat...
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