Preparing a Percent Solution by Mass
Developed from SciTek
Background:
Sugar-based corn syrup is one of the main components of colas. The sugar content of the corn
syrup used to make a soft drink determines the soft drink’s level of sweetness. In this laboratory session
you will be learning how to make solutions containing different amounts of table sugar (sucrose). In a
subsequent session, you will use these solutions to learn how technicians test corn syrup, and soft drinks
containing corn syrup, for their sugar content.
The method you will use to make the sugar solutions involves mass percentage. This is the
number of grams of solute (sugar) per 100g of solution (sugar dissolved in a solvent). You will measure
the masses of the sugar and the solution using an electronic balance.
Procedure:
1. To make a 10% solution by mass of sucrose, every 100 g of your prepared solution needs to
contain 10.0g of sucrose.
2. You will use distilled water as your solvent.
3. Using an electronic balance, find the mass of an empty Styrofoam cup (A). Record
this value in your data table.
4. Add sucrose (table sugar) to the cup until the measured mass is 10.0g greater than the mass
of the empty cup. Record this value in your data table (B).
5. Calculate the total mass of sucrose added to the cup (B-A). Record this in your data table. This value
should be as close to 10.0g as possible.
6. Add distilled water to the sucrose in the cup until the total measured mass is
100 g greater than the mass of the EMPTY cup. Record this value in your data
Table (C).
7. Calculate the mass of solution by subtracting (C)-(A). The value should be as close to 100g as
possible.
8. Stir with a glass stirring rod until the sucrose dissolves completely. You now have a 10%
solution by mass of sucrose and water.
9. Pour your solution into a beaker labeled 10% sucrose in water.
10. Rinse out your cup with water and dry it completely.
11. Repeat procedure to make 20%, 30%, and 40% solutions. You will use 20g, 30g, and 40g of sucrose
respectively. You should always end with 100g total solution for each sample.
12. Be sure to reweigh your cup each time.
13. All four solutions will need to be covered with plastic film so as to prevent evaporation.
14. Store your labeled, covered solutions in your lab drawer. You will use these
solutions in the next lab.
15. Clean your area, glassware, and balance. Store you equipment in its proper place and have your
teacher check you out of lab.
Safety:
1. Do not taste any of the solutions.
2. You must wear safety goggles at all times when working in the laboratory.
Data Table:
%
Mass of empty
sucrose
cup (g)
A
Mass of cup +
sucrose (g)
B
Mass of
sucrose (g)
(B-A=mass of
sucrose)
Mass of cup +
sucrose + water
(g)
C
Mass of solution
(g)
(C-A= mass of
solution)
10%
20%
30%
40%
Calculations:
1. Verify that each solution you created is the appropriate percentage. Show your calculations for each %
solution below.
a.
b.
c.
d.
Conclusion:
In your summary, relate this lab to the carbonated beverage industry. How is this lab purposeful
in solving the problem we are trying to solve?