Types of Solutions Discovery Activity
Objective: I can define and describe the following terms: solvent, solute, miscible, immiscible,
electrolyte, nonelectrolyte, saturated, unsaturated, and supersaturated.
Here’s a link to an intro video that might be helpful: http://goo.gl/L8HPEm
Part 1: What is a mixture?
a. Beaker A - Add 25mL of water to a small beaker. The water is considered a pure substance.
b. To the beaker add 1 spoonful of sodium chloride and stir. This is now considered a
homogenous mixture or a solution. The salt is the solute and the water is the solvent.
c. Beaker B - In a second beaker add 1 spoonful of sucrose (table sugar-C12H22O11) to 25mL of
water and stir. This is also considered a homogenous mixture or solution. The sugar is the
solute and the water is the solvent.
d. Beaker C -To a third beaker add 1 spoonful of sodium bicarbonate to 25mL of water.
e. Beaker D – Add 1 spoonful of calcium carbonate to 25mL of water. This is considered a
heterogeneous mixture.
f. Beaker E – Add 25mL of carbonated soda to a beaker. This is considered a heterogeneous
mixture.
Questions:
a. Classify the following as a pure substance, heterogeneous mixture, or solution
(homogenous mixture)
a. Salt water
d. Bronze
b. River water
e. Air
c. Gold
f. Blood
b. In beakers C, D, and E identify the solute and solvent
Beakers
C
D
E
c. Define the following:
a. Solute
b. Solvent
Solute
Solvent
Part 2: Electrolyte vs. Nonelectrolytes
a. Test Beakers A-D with the conductivity tester to determine if they conduct electricity. Place a
check in the appropriate column.
Beaker
Electrolyte
Nonelectrolyte
A
B
C
D
E
b. Watch the following video. http://goo.gl/xtL9vR
a. What must be present in order for solutions to conduct electricity? Why?
Part 3: Miscible vs. Immiscible Liquids:
a. Pour 25mL of water into a small beaker. Add 10mL of vegetable oil to the beaker. The oil is
considered to be immiscible in the water.
b. Add three drops to the oil and water mixture and observe.
c. To determine if something is miscible you can often apply the phrase “like dissolves like”.
a. This refers to fact that most polar molecules can dissolve polar molecules and nonpolar
molecules can dissolve nonpolar molecules. (Note: Most ionic compounds will also
dissolve in water)
b. POLARITY REMINDERS
i. To be polar, a molecule does not have an even distribution of charge (electrons
are NOT shared evenly between elements). This is based on its VSEPR shape.
1. In most cases, a molecule is polar if one of two things is present:
a. Lone pair of electrons on the central atom
b. Different elements are attached to the central atom
ii. To be nonpolar, a molecule has an even distribution of charge throughout the
entire structure.
1. In most cases, a molecule is nonpolar if there are no lone pairs on the
central atom AND all atoms attached are the same element.
d. Looking at your beaker, what could you hypothesize about the polarity of food coloring?
Questions:
a. Predict the miscibility of the following in water:
Substance
Lewis Dot Structure
Polarity
Will dissolve in water?
(Yes or No)
Ammonia
(NH3)
Benzene
(C6H6)
Rubbing
Alcohol
(C3H7OH)
Part 4: Saturation
a. Google Chemistry Phet – Salts and Solubility or go to the link http://goo.gl/ZwVoLl
This must be done on a laptop!
b. Add three shakes of salt to the water. You will notice that everything is dissolved. Nothing is
still bound together. Out of the terms unsaturated, saturated, and supersaturated, which do
you think this solution is?
c. Continue adding salt until you have bound particles. There are bound particles because the
solvent cannot dissolve any more solute. Out of the terms unsaturated, saturated, and
supersaturated, which do you think this solution is?
d. The remaining type of solution must be heated in order to dissolve the bound particles that
remain. Out of the terms unsaturated, saturated, and supersaturated, which do you think this
solution is?
Questions:
a. Define the following:
a. Unsaturated solution
b. Saturated solution
c. Supersaturated solution
Part 5: Factors Affecting Solubility
Below are statements about the dissolving process Explain each one at the molecular level.
a. Increasing the pressure of a solute gas above a liquid solution increases the solubility
of the gas in the liquid. Why?
b. Increasing the temperature of water speeds up the rate at which many solids dissolve
in the solvent. Why?
i. We see the opposite happen gases are the solute. Why?
c. Increasing the surface area of a solute speeds up the rate at which it dissolves in a
liquid solvent. Why?
Here’s a link to a video with great explanations about why the factors affect the solubility:
http://goo.gl/xL06NH OR you can use a textbook (page 401-402 and 407-408).
Conclusion Questions:
1. What type of compounds (type of bond) are electrolytes? What do you think makes a
substance a good conductor?
2. Identify each of the following substances as an electrolyte or nonelectrolyte.
a. Water
d. Rubbing alcohol (C3H7OH)
b. Salt water
e. HCl
c. Kool-aid
f. CuSO4
3. Someone used a permanent marker on the white board. Water is not working to remove
(dissolve) it. Which of the following substances could work better? Why?
a. HCl
b. CCl4
c. NH3
d. C6H12
4. In the lab, you have three beakers of different concentrations of the same solution. You
decide to test what type of solution each is by adding another crystal of the solute to each
beaker. (think of your phet to help answer these questions)
a. In the first beaker, the crystal sinks straight to the bottom. What type of solution was in
this beaker? Why?
b. In the second beaker, the crystal dissolves into the solution. What type of solution was
in this beaker? Why?
c. In the last beaker, the crystal causes the entire solution to crystallize. What type of
solution was in this beaker? Why?
5. Describe the best conditions to bottle soda to get the most dissolved carbon dioxide.