Solutions Lab Report
Instructions: In this laboratory activity, you will investigate how temperature, agitation, particle size, and dilution affect the taste of a drink. Fill in each section of this lab report and submit it and your pre-lab answers to your instructor for grading.
1. Write a hypothesis that predicts how each solubility factor will affect the solution. Does it make it sweeter, watery, murky, or grainy? How does it compare to the control drink made according to the powdered drink mix package? The solubility factors to test are heating the solvent, stirring the solvent, and decreasing the particle size before dissolving the drink mix in the solvent.
An example hypothesis could be: Heating up a solvent increases the sweet taste of a powdered drink mix.
A list of materials and summary of steps has been provided for you. List and explain your controlled variables, independent variable, and dependent variable for this lab.
· 13 plastic cups (12 oz)
· permanent marker for labeling
· measuring stick
· tablespoon and teaspoon
· kitchen scale that measures in grams (optional)
· source of heat
· granulated sugar
· sugar cubes
· spoon for stirring
· 3–4 packages of powdered drink mix (6.6 ounces per package)
Remember, controlled variables are factors that remain the same throughout the experiment. An independent (test) variable changes so that the experimenter can see the effect on other variables. The dependent (outcome) variable will change in response to the test variable.
Summary of Steps:
1. Measure 2.5 cm from the bottom of each plastic cup and draw a line. Filling to this line will represent approximately 100 mL for each cup.
2. Label one cup "Control." Label three cups for each molarity (1.0 M and 0.5 M).
3. Label one cup for each molarity with the solubility factor being tested. Labels are listed below:
· 1.0 M without heat
· 0.5 M without heat
· 1.0 M with heat
· 0.5 M with heat
· 1.0 M with stir
· 0.5.M with stir
· 1.0 M without stir
· 0.5 M without stir
· 1.0 M with sugar
· 0.5 M with sugar
· 1.0 M with sugar cubes
· 0.5 M with sugar cubes
4. Mix the fruit mix according to the recipe on the package. Once complete, pour the fruit drink into the cup labeled "Control" to the 2.5 cm line.
5. Using the mass values from your pre-lab, create 1.0 M and 0.5 M solutions of fruit drink mix for your 1.0 M and 0.5 M cups. If you do not have a kitchen scale that measures in grams, use 1 tablespoon = 12.5 g and 1 teaspoon = 4 g as approximate measurements.
6. Test each solubility factor for each molarity but not your control solution. See procedures below.
Test one—Temperature: Mix 1 teaspoon of sugar in the room temperature drink solution in the 1.0 M without heat and 0.5 M without heat cups. Mix 1 teaspoon of sugar in hot drink solution in the 1.0 M with heat and 0.5 M with heat cups.
Test two—Agitation: Mix 1 teaspoon of sugar in the 1.0 M with stir, 1.0 M without stir, 0.5 M with stir, and 0.5 M without stir cups. Stir the solution in the 1.0 M with stir and 0.5 M with stir cups for 30 seconds. Leave the other solutions unstirred.
Test three—Particle size: Mix 1 teaspoon of sugar in the 1.0 M with sugar and 0.5 M with sugar cups. Drop 1 sugar cube in the 1.0 M with sugar cubes and 0.5 M with sugar cubes cups.
1 sugar cube = 1 teaspoon sugar
7. Time to taste test. Record your observations of taste, color, and texture for each solution in the data tables. Be sure to drink water between taste tests to clear your palate.
1.0 M without heat
0.5 M without heat
1.0 M with heat
0.5 M with heat
1.0 M with stir
0.5 M with stir
1.0 M without stir
0.5 M without stir
1.0 M with sugar
0.5 M with sugar
1.0 M w sugar cubes
0.5 M w sugar cubes
Write a conclusion statement that addresses the following questions:
· How did your observations help you infer the solubility of each solution?
· How did temperature, agitation, and particle size affect solubility?
· Do your data support or fail to support your hypothesis (include examples)?
· How do you think the investigation can be explored further?
Post-Lab Reflection Questions
Answer the reflection questions using what you have learned from the lesson and your experimental data. It will be helpful to refer to your chemistry journal notes. Answer questions in complete sentences.
1. If you were working for a beverage company, which molarity would you recommend, and what directions for mixing would you create for the drink package? Support your claims using the data you collected.
2. What do you think would happen to the solute in a heated solution if you cooled it? Explain your answer.
3. If you needed to make 100 mL of a 0.2 M fruit drink solution from the 1.0 M fruit drink solution, how would you do it? (Hint: Use MsVs = MdVd to find the amount of concentrated solution you need, then add water to reach 100 mL.) Show your work.
4. Baking soda (NaHCO3) can be added to a fruit mix solution to create a carbonated drink. An example is the reaction between baking soda and citric acid below.
C6H8O7 + 3NaHCO3 → Na3C6H5O7 + 3H2O + 3CO2
a. What is the molar mass of citric acid (C6H8O7) and baking soda (NaHCO3)?
b. How many milliliters of a 0.8 M solution of citric acid would be needed to react with 15 grams of baking soda? Show your work.