DON’T WRITE ON
THIS PAPER!
Solubility Lab
1. At the top of a new page in your comp. book write a title for this lab using the Student Lab Write-Up
Format found in the back of your comp book.
2. Write a heading ‘Introduction’ at the left of the page and use the Student Lab Write-Up Format to write
your introduction in paragraph form. The last sentence of this paragraph should be your hypothesis which is to
be written using the format found on the Student Lab Write-Up Format page. Underline the entire
hypothesis! Write your hypothesis predicting which you think will cause the Alka Seltzer to dissolve the
fastest (cold water, hot water, agitation, smaller particle size).
Definitions to know and help with this lab:
Dissolve
The act of taking one substance and combining it with another substance so that they mix
to make a uniform solution of the two – when a substance disappears into a liquid.
Solution
The amount of a substance (called the solute) that can be dissolved in a given amount of
liquid (known as the solvent).
Solute
A substance that is dissolved in another substance.
Solvent
Substances (usually liquid) capable of dissolving or dispersing one or more other
substances. Water is known as the universal solvent.
Solubility
The amount of a substance (called the solute) that can be dissolved in a given amount of
liquid (known as the solvent). (example: 20 ml of sugar into 1000 ml of water)
Insoluble
The inability of a substance to be dissolved in another substance. (none of the solute
disappears in the solvent)
Rate of Solubility
How fast the solute dissolves into the solvent.
Surface Area
(particle size)
How much exposed area a solid object has.
Agitation
(stirring or shaking)
To spread the solute evenly throughout the solvent.
Draw this data table into your comp book, only use six lines. (Remember to draw with a straight edge)
Independent Variable
Dependent Variable
Room Temp. (control)
min.
Agitation (stirring)
min.
Surface Area (crushed)
min.
Temp. (Cold)
min.
Temp. (Hot)
min.
Directions:
Step 1 Room Temp - Fill your container to the black line with room temperature water, get an Alka-Seltzer
tablet from your teacher, make sure you have a stop watch ready, carefully place (don’t drop) the tablet in the
water and time how long it takes to dissolve completely. Record data on data table. Rinse out the container
and flush down the sink when done.
Step 2 Stirring - Fill your container to the black line with room temperature water and place an Alka-Seltzer
tablet into the water the same way you did the first time. Constantly stir back and forth with your plastic
spoon until it completely dissolves. Record how long it took to dissolve completely. Rinse out the container
and flush down the sink when done.
Step 3 Surface Area - Fill your container to the black line with room temperature water. Place an Alka-Seltzer
in the package and use the heel of your hand to crush it into small pieces. Carefully pour it into the water, and
time how long it takes to dissolve completely. Record data on data table. Rinse out the container and flush
down the sink when done.
Step 4 COLD Water - Fill your container to the black line with COLD water. In the same way you did earlier,
carefully place a whole tablet in cold water and time how long it takes to dissolve. Rinse out the container and
flush down the sink when done.
Step 5 HOT Water - Fill your container to the black line with HOT water. In the same way you did earlier,
carefully place a whole tablet in hot water and time how long it takes to dissolve. Rinse out the container and
flush down the sink when done.
Step 6 Clean UP – Dry out your container with a paper towel and put it on the counter to dry Then, answer
Post Lab Questions in your comp. book. Copy the questions and answer them into your comp. book!
Post Lab Questions:
1.
2.
3.
4.
5.
6.
7.
8.
What was your control group in this experiment?
Name two controlled variables or constants:
What was the solvent in each of these trials?
What was the solute in each of these trials?
How do you know when a solute has completely dissolved in a solvent?
What effect did agitation have on the solubility rate of the Alka Seltzer?
What effect did surface area have on the solubility rate of the Alka Seltzer
What effect did temperature have on the solubility rate of the Alka Seltzer?