Chemical Weathering Lab
**What is the recipe for an environment that causes the most rapid chemical weathering?
The breakdown and erosion of rocks caused by chemical reactions is called
chemical weathering. Unlike physical weathering, in this type of weathering, the bonds holding the
elements in a rock together are broken. New substances are formed as a result.
Antacid tablets (like Tums) are chemically engineered in the lab setting and contain Calcium
carbonate. Chalk is a type of sedimentary rock, limestone, and is formed in nature. It is made of the shells of
microscopic organisms and is also made of Calcium carbonate. In this lab, we will use antacid tablets to
determine the factors that most affect the rate of chemical weathering. We’ll investigate acidity, surface area
and temperature.
Materials
 6 Antacid tablets (Tums)
 Piece of paper towel (use as a place mat)
 2 small beakers--one labeled “A”, one labeled “B” (put labels on your place mat)
 Water (from sink)
 hot plate/burner (teacher use only)
 Room temperature white vinegar (in jugs up front)
 pH paper (they help to determine how acidic a solution is)
 safety glasses
Procedure:
Alert !!
Put safety glasses on prior to and during ALL your work with the vinegar
Acidity Test
1. Pour 50 mL of vinegar into one beaker A. Pour 50 mL water into beaker B.
2. Use pH paper to dip into and determine the pH of each solution & record in the data table.
Use the color chart on the vial of pH paper (on brown table up front)
3. Place one antacid tablet in each beaker.
4. Observe each beaker for at least one minute and record your observations in the data table.
5. Pour liquids (and tablets?) into the disposal bucket at front of room. Tablets will go into the garbage
Surface Area Test
1.
2.
3.
4.
5.
Pour 50 mL of room temp vinegar into EACH beaker
Place one (whole piece) antacid tablet in one of the beakers.
Break the other tablet into 4 smaller pieces. (Make sure all parts are put into the beaker!)
Observe each beaker for at least one minute and record your observations in the data table.
Pour liquids (and tablets?) into the disposal bucket at front of room. Tablets will go into the garbage.
Temperature Test
1.
2.
3.
4.
5.
\
Pour 50 mL of room temperature vinegar into beaker A.
Get 50 mL of WARM vinegar from your teacher and pour into beaker B.
Place one tablet into the warm vinegar and one tablet into the room temperature vinegar.
Observe each beaker for at least one minute and record your observations in the data table.
Pour liquids (and tablets?) into the disposal bucket at front of room. Tablets will go into the garbage.
Chemical Weathering Lab Data & Conclusions Log
Name ____________________ Hr. ___
**What is the recipe for an environment that causes the most rapid chemical weathering?
Observations: Amount of Reaction (how many bubbles)
(Check the appropriate box or boxes)
Test
None
Some
More than
other beaker
Any other unique
observations
or measurements?
Acidity Test
Tablet in Water
pH(water)=
Tablet in Vinegar
pH(vinegar)=
Surface Area Test
Whole tablet
Broken tablet
(increases surf. area)
Temperature Test
Room Temp. Vinegar
Heated Vinegar
Make (bar) graphs below to show the pH differences AND how acidity, surface area, & temperature
affect chemical weathering: (**Remember...Graphs have a legend (a key), a title, and have the axis labeled!)
Title: __________________________________________
Label
this axis
with pH
numbers
Label this
axis with
the
bubbling
amounts
Label this axis with the tests you were performing
Answer the following questions after analyzing your data:
1. What is your claim? How is the rate of chemical weathering affected by ___?
a. Acidity… ____________________________________________________________________
______________________________________________________________________________
b. Surface Area…________________________________________________________________
(FYI: When you break something into pieces, there is actually more surface exposed than when whole)
______________________________________________________________________________
c. Temperature…________________________________________________________________
______________________________________________________________________________
2.
What type of weathering did this lab show? _________________________________
How? _____________________________________________________________________________
____________________________________________________________________________________
3.
Based on your data, list the factors (Acidity, Surface Area, Temperature) in order
from GREATEST to LEAST effects on the rate of chemical weathering. Explain how you did this!
(1) most =____________________ (2) ______________________ (3) least=____________________
____________________________________________________________________________________
4.
Remember that antacid tablets are made of the same compound as chalk, Calcium carbonate. Tablets
are chemically engineered in a lab setting, chalk is made naturally in nature. Determine what type of rock
chalk is (Sedimentary, Igneous, Metamorphic?) (You might need to Google this!) Look up what mineral it
contains that reacts with vinegar (or any other acid!). Record the chemical reaction that occurs?
________________________________
__________________________________________________________________________________________
5.
Based on your observations in this lab, describe the conditions that would cause the MOST chemical
weathering to occur.
__________________________________________________________________________________________
__________________________________________________________________________________________________
Where on Earth might you find these conditions? ____________________________________