Part 1 – Density of Liquids
1. Using the balance, determine the mass of an empty 10 ml graduated cylinder to the nearest 0.01g.
Record the value in Data Table 1.
2. Add 5 – 7 ml of unknown liquid 1 into the graduated cylinder. Determine the volume to the nearest
0.05 ml and record the value in Data Table 1. Determine the mass of the cylinder and liquid and record
that in the data table.
3. Rinse out the graduated cylinder with water and dry it as well as possible. (If available, use a
second, dry graduated cylinder.)
4. Repeat steps 1,2, and 3 with unknown liquid 2. record all determinations in Data Table 1.
DATA TABLE 1
Liquid 1
Liquid 2
1a. Mass of graduated cylinder (g)
1b. Volume of liquid (ml)
1c. Mass of cylinder + liquid (g)
CALCULATION TABLE 1
Liquid 1
Liquid 2
1A. Mass of liquid (1c – 1a)
1B. Volume of liquid (1b)
1C. Density of liquid (1A/1B)
CALCULATION TABLE 2
Liquid 1
2A. Identity from Table 1
2B. Experimental Value for Density (1C)
2C. Accepted Value from Table 1
2D. Experimental Error (2B – 2C)
2E. % Error (2D/2C x 100%)
Liquid 2
Part 2 – Density of Solids
1. To the graduated cylinder add about 5 ml of water. Determine the volume of the water to the nearest
0.05 ml and record the value in Data Table 2.
2. Obtain a metal shot sample from the central lab bench. Obtain enough sample to change the volume
of the liquid in the cylinder by 2 –3 ml. (Just enough shot to barely cover the bottom of the small cup.)
3. Use the balance to determine the mass of the empty plastic cup to the nearest 0.01 g. Record the
mass of the cup in Data Table 2.
4. Place the metal shot in the plastic cup and determine the mass of the cup with the metal shot to the
nearest 0.01 g. Record the mass of the metal shot plus the cup in Data Table 2.
5. Determine the volume of the combined water and metal in the graduated cylinder. Record the value
in Data Table 2.
6. Carefully pour off the water and collect the metal shot on a paper towel to dry. Transfer the shot to a
watch glass to allow more time for it dry. At the end of the lab period place the damp shot in labeled
beaker on the central lab table.
7. Repeat steps 1 – 6 for the other 2 metals.
DATA TABLE 2
Metal A
Metal B
Metal C
Metal B
Metal C
Identity of Metal
2a. Volume of water (ml)
2b. Mass of cup (g)
2c. Mass of cup + metal (g)
2d. Volume of water + metal (ml)
CALCULATION TABLE 3
Metal A
3A. Mass of metal (2c – 2b)
3B. Volume of metal (2d – 2a)
3C. Density of metal (3A/3B)
3D. Accepted value from Table 1
Part 3 – Analysis of Data
A. Graphing
1. Collect the mass and volume data for Part 2 from the other lab groups in your class. Compile th data
in Data Table 3.
2. Plot the data from all groups on one graph using different lines for each metal. Let the x-axis
represent volume (0 – 5 ml) and the y-axis represent mass (0 – 50 g).
DATA TABLE 3
(From CALCULATION TABLE 3)
Lab
Group
Metal A
Mass
(g)
Metal A
Volume
( ml)
Metal B
Mass
(g)
Metal B
Volume
(ml)
Metal C
Mass
(g)
Metal C
Volume
(ml)
1
2
3
4
5
6
7
8
B. Experimental Precision and Accuracy
1. Generate a value for the density of each metal by calculating the slope of the line for each of the
metals plotted above. Record your values in Calculation Table 4.
Slope =
Metal 1 Slope:
y =
x
M
V
= Density
Metal 2 Slope:
Metal 3 Slope:
2. Compare each slope to the accepted value for the density of each metal by calculating the
experimental error and percent error for each metal. Record your values in Calculation Table 4.
CALCULATION TABLE 4
Metal
A
Slope
Accepted Value
Experimental Value
% Error
B
C
3. Using the data for each lab group in Data Table 3, calculate the density for each metal and the
average value for the density of each metal. Record your values in Calculation Table 5.
CALCULATION TABLE 5
Lab Group
A
B
C
1
2
3
4
5
6
7
8
Average
Density
4. Compute the absolute deviation(Da) for each of the measurements of one of the metals in
Calculation Table 5. ( Da = Experimental Value – Average Value )
5. Calculate the Average Deviation for the data in Calculation Table 6 and write the value at the bottom
of the table.
6. The uncertainty is the average deviation preceded by a +/- sign. Include this in Data Table 6.
CALCULATION TABLE 6
Lab Group
Da
1
2
3
4
5
6
7
8
Average Deviation =
Uncertainty = +/-
Experimental Value expressed as Average Value +/- Average Deviation :
Part 4 – Conclusions
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Compete the following on a separate sheet of paper.
Please write in complete sentences and in paragraph form.
Be thorough and concise in your answers.
1. Explain what your graphed data demonstrates regarding the density of different substances and what
it demonstrates regarding the density of the same substance as the volume of the substance changes.
2. Explain why the each slope obtained from your graphed data should give a more accurate value for
the density of each metal as compared to the measurement of a single lab group.
3. Discuss the difference between accuracy and precision of a set of measurements. What
mathematical determinations are used to quantify each of these?
4. From your density determinations of the two liquids, was your experimental data accurate? Explain.
5. From your average density determinations of the three metals, was the experimental data accurate?
Was it precise? Explain.
6. Explain what “Experimental Value expressed as Average Value +/- Average Deviation” means.
(What does this numerical value/range actually tell you?)
7. Discuss the possible sources of error in your lab procedure and how these errors may have affected
your density determinations.