Kylie Salcido
Beverage Density Lab Report
Period 7
10/7/13
Background
Density is figured out by measuring the mass and volume of a substance and then dividing the two. Mass can
be measured with a balance, where as volume can be measured with a graduated cylinder. The density of a
solution depends on the concentration of solute. The higher the solute value, the more the density, the lower
the solute value, the lower the density. To express concentration, scientists use units that have to do with
weight.
In this lab, we will be calculating and measuring the mass and volume of different beverages to figure
out its percent sugar and it’s over all density.
Hypothesis
If we color code different beverages and separate them by known amounts of sugar, then we will be able to
determine the percent sugar content of each beverage.
Experiment Overview
The purpose of this experiment is to determine the percent sugar content in
beverages. The density of five sugar “reference” solutions will be measured in
Part A. The reference solutions contain known amounts of sugar (0-20%) and
have been dyed with food coloring to make it easier to tell them apart. Their
densities will be plotted on a graph to obtain a calibration curve of density versus
percent sugar concentration. In Part B, the densities of four beverages and an unknown will also
be determined and the calibration curve used to find how much sugar they contain.
The results will be compared again the information provided on the nutrition
labels for these beverages.
Purpose:
To construct a graph of sugar content versus density for 5 sugar solutions.
To determine the sugar content of 4 beverages and an unknown using graphical analysis.
Materials:
balance small beaker, 5 sugar solutions graduated cylinder, 4 beverages plus unknown
Safety: goggles, glass breakage, spills
Data Table A: Density of Reference Solutions
Solution
Mass, g
Sample Volume,
mL
Density, g/mL
0% Sugar
9.46 g
10.00
0.946 g/mL
5% Sugar
9.71 g
10.00
0.971 g/mL
10% Sugar
9.97 g
10.00
0.997 g/mL
15% Sugar
10.43 g
10.00
1.043 g/mL
20% Sugar
10.64 g
10.00
1.064 g/mL
Data Table B: Beverage Densities
Beverage
Sample Volume,
mL
Mass, g
Density, g/mL
Pepsi
10.14 g
10.00
1.014 g/mL
Diet Pepsi
9.85 g
10.00
.985 g/mL
Apple Juice
10.07 g
10.00
1.007 g/mL
Lemonade
9.95 g
10.00
.995 g/mL
Powerade
10.19 g
10.00
1.019 g/mL
Unknown
_____
10.16 g
10.00
Results Table:
Beverage
Experimental % sugar
9.5%
Powerade
5%
Diet Pepsi
Pepsi
8.5%
Apple Juice
7%
Lemonade
5.5%
Post-Lab: Results Table
1.016
Beverage
Measured
Percent sugar
density,
(experimental)
g/mL
Powerade
1.019 g/mL
pepsi
1.014 g/mL
Apple Juice
Amount of
sugar
(Nutrition
label)
Percent
sugar
(calculated
from
Nutrition
label)
Percent
error
21 g/350 mL
5.7%
66.67%
8.5%
41 g/355 mL
11.4%
25.4%
1.007 g/mL
7%
27 g/240 mL
11.2%
37.5%
Diet pepsi
.985 g/mL
5%
0 g/355 mL
0%
0%
Lemonade
.995 g/mL
5.5%
31 g/240 mL
13%
57.7%
9.5%
Post-Lab Calculations and Analysis
1.
2.
3.
4.
Plot density versus concentration for the five reference solutions on a graph. The
concentration is the independent variable (x-axis) and the density is the dependent
variable (y-axis). Use a ruler to draw the “best-fit” straight line through the data points.
Use the graph to estimate the unknown sugar concentrations in the first beverage. To do
this, locate the point on the y-axis that corresponds to the density value of the
beverage. Follow the point on the y-axis across horizontally to where it meets the “best
fit” straight line through the data. Now read down vertically from this point on the
“best fit” line to the x-axis. The point where this vertical “line” meets the x-axis equals
the percent concentration of sugar in the beverage solution. Construct a Results Table
and record the density of the beverage and the estimated percent sugar concentration.
Repeat step 2 to determine the percent sugar concentration of the second beverage.
Record all information in your Results Table.
Calculate the actual or accepted value of the sugar concentration in weight percent for
each beverage, using the nutrition label information and the measured density value. Hint:
See Pre-Lab Question #3 for how to do this calculation. Record both the nutrition label
information and the actual percent sugar concentration in your Results Table.
5.
6.
7.
Use the following equation to calculate the percent error in our experimental
determination of the sugar content in each beverage. Enter the percent error in the
Results Table.
What was your measured density for pure water (0% sugar solution)? The density of
water is usually quoted as 1.0 g/mL, but the precise value is for 4oC. Comment on why
your measured density might be higher or lower than 1.00 g/mL.
This lab looks at the relationship between the density of a beverage and its sugar
content. What assumption is made concerning the other ingredients in the beverage and
their effect on the density of the solution? Do you think this is a valid assumption?
Explain
The assumption of the other ingredients of the beverage is that it does not affect the percent sugar. I am not
sure if this is a valid assumption.
8.
When plotting data such as that obtained in this experiment, why is it not appropriate to
“connect the dots?” If you were to repeat the lab, do you think you would get exactly
the same results? Comment on the sources of error in this experiment and their likely
effect on the results.
It is important not to connect the dots because the line must be straight in order to get the experimental
percent. The line will not be straight if you connect the dots, so it is important to draw the line between the dots
if the line is not going to be straight. If the lab was repeated, I do not think all of the results would be the same.
Liquid substances can get caught onto cups an other materials, causing the measurements to be slightly off each
time.
Conclusion
After completing the lab, I was able to conclude my hypothesis correct. We were able to calculate the percent
sugar of each beverage by separating them by their known amounts of sugar and measuring the mass and
volume of each. By measuring the correct amount of liquids in each measurement, my lab group and I were
able to calculate the percent sugar by graphs we created on our own, and exact calculations using the
nutrition label. The percentages were different of course, so we also calculated the percent error of the sugar
calculations. Overall, through careful direction and technique, the lab was successful.