Name(s Bill Wagenborg and Richard Matthews
Chemistry 511
Experiment: Initial Investigations into Measurements and Density.
Lab Report – Submit electronically (digital drop box) by ___________________
Note: When submitting to digital Drop Box label your files with your name first and
then a brief description of what the document is. (For example, a submission by John
Smith would be: Smithdenistylab)
FORMULA: Density = Mass/Volume
DATA/CALCULATIONS:
Note: Data and Calculations may be completed on an excel spreadsheet.
Part 1- Density of a Liquid:
Mass of cylinder: _71.0591 g______
Mass of Cylinder +
Alcohol
78.9654 g
86.6335 g
94.3628 g
102.2657 g
Mass of Alcohol
7.9063 g
15.5744 g
23.3037 g
31.2066 g
Average Density
Volume of Alcohol
10 ml
20 ml
30 ml
40 ml
Density
.79 g/ ml
.77872 g/ ml
.77679 g /ml
.78 g / ml
.7813775
Using Excel, create a point/line graph of Mass of Alcohol vs. Volume. Obtain the
equation for the line and display it on the graph. Submit the graph along with your
report. (You can cut and paste into this document if you choose.)
Mass of Alcohol vs Volume
Mass of Alcohol (g)
35
y = 0.7763x + 0.0902
R2 = 1
30
25
Series1
20
Linear (Series1)
15
Linear (Series1)
10
5
0
0
10
20
30
40
50
Volume of Alcohol (ml)
Part 2 – Density of a solid:
Mass
Volume Initial
Volume Final
21.5808 g
20 ml
23 ml
Part 3 - Conservation of Volume:
Volume of Alcohol
20 ml
Volume of Water
20 ml
Volume of Object
3 ml
Density
7.1936 g /ml =
Volume of Mixture
38 ml
CONCLUSION QUESTIONS
Part 1- Density of a Liquid:
1. Compare your average density value to the slope of your mass vs. volume graph.
Are they close? Should they be? What does the slope of a mass vs. volume graph
represent?
Our average density was .7813775 ml and our slope of the graph was .7763.which is
close. They should be close because the slope of the graph shows density (since it is
found by mass/ volume)
2. For analytical work, a minimum of three trials are required. Why do you think this is
necessary?
Numerous trials allow us to come up with an average which decreases margin of
error and checks for consistency. We can catch more easily extreme answers on the
high and low scale.
Part 2 – Density of a solid:
1. Why did you measure the mass of the solid first then determine the volume?
We measure the mass first because it needs to be completely dry and not affected by
the water. In order to find its volume we needed to drop it in the water to find
displacement.
2. Can the water displacement method be used for all solids? Why or why not?
It can only be used for solids that are not soluble and those that are denser than water.
3. Some of you choose to use a penny as your “solid object” in Part 2 of this procedure.
Some decided to use multiple pennies. What experimental values change when the
numbers of pennies change? What (if any) experimental values do not change? Discuss.
When you use multiple solids the mass of the solid will change and the volume of the
solid will change but the volume will not change. The ratio of mass to volume is still
the same because the mass changes by the same factor as the volume does. Thus
when you divide it is the same answer.
Part 3 - Conservation of Volume:
1. Was volume conserved in this experiment?
No volume was not conserved in the experiment, it was lost. (2 ml)
2. Let a = alcohol, w = water, mix = alcohol and water mixture
If we accept the Law of Conservation of Mass, then,
Ma + Mw = Mmix
Given that D = M/V, M= D*V
Substituting,
Da*Va + Dw*Vw = Dmix*Vmix
Assuming the above to be true, under what conditions will volume be conserved?
Use your experimental value for the density of alcohol (in part one) and assume the
density of water to be 1.00 g/ml, support your argument.
In order for volume to be conserved, the density of the water and the density of the
alcohol would have to be the same. In this case they are not. Alcohol (from our data)
has a density of .78 g/ml and water has 1.00 g/ml. In our finding we discovered that
matter was lost. If the densities were the same it would have produced a volume of
40 ml which in turn would have conserved volume.