Lab #10: Chemical Weathering Purpose In this experiment, you will learn the importance, abundance and some of the reactions of calcium and other carbonates normally found in Earth’s crust. You will explore how different types of rocks react to some of the weathering agents such as water and acid. Materials · Vinegar · Lemon juice · Water · Clear plastic cups · Dropper or plastic pipette · Pieces of white chalk · Optional- different rock types (quartz or granite) Introduction The Earth is not homogeneous and is composed of different layers. Each layer has a different composition. The lithosphere is the rigid outer layer that contains the crust and upper mantle. The lithosphere is composed of three equally important components, namely, inorganic (rocks and mineral), organic (soil and fossil fuel), and biological (flora and fauna). Our focus for this chapter and activity is on inorganic components. Chemical Weathering Rocks and mineral are all around us. Watch this video to understand the difference between rocks and minerals. Weathering describes the breaking down or dissolving of rocks and minerals on the surface of the Earth. Water, ice, acids, salts, plants, animals, and changes in temperature are all agents of weathering. Weathering wears away exposed surfaces over time. Chemical weathering occurs at a second stage of rock disintegration in which small pieces of rock produced by physical weathering are then further broken apart by chemical processes such acid reactions, hydrolysis and oxidation. Acid rain is formed when certain pollutants dissolve in rain creating stronger acids. Learn more about acid rain here. Acid rain is one factor that can increase the rate of erosion, with effects that can be seen in just a few decades. Limestone and marble are composed calcium carbonate, the same material as chalk, and are commonly used for constructing buildings and statues. Rain that is too acidic will “eat away” at these structures very quickly. Acids in rain such as sulfuric acid (H2SO4) dissolves the calcium carbonate to make a moderately soluble form of calcium, CaSO4 (called gypsum), along with carbon dioxide and water. This is an acid-base neutralization. This could also have positive impact: the regions where the bedrock or soil contain large amounts of limestone are less likely to have polluted water due to acid rain than areas with igneous bedrock. This is because the limestone (which is a base) is able to neutralize acid rain before it gets into the lakes and rivers. This means that damage due to acid rain depends on both the pH (amount of acid in a substance) of the rain and the type of soil/bedrock. In this activity, you will explore the effect of acetic acid (found in vinegar) and lemon juice on chalk. You can also repeat this activity with other rocks (if available) and record your observations. Procedure Prepare three clear plastic cups and label them as water (W), vinegar (V), and lemon juice (L). Add about 20 ml of ea ...

1. Lab #10: Chemical Weathering
Purpose
In this experiment, you will learn the importance,
abundance and some of the reactions of calcium and other
carbonates normally found in Earth’s crust. You will explore
how different types of rocks react to some of the weathering
agents such as water and acid.
Materials
· Vinegar
· Lemon juice
· Water
· Clear plastic cups
· Dropper or plastic pipette
· Pieces of white chalk
· Optional- different rock types (quartz or granite)
Introduction
The Earth is not homogeneous and is composed of different
layers. Each layer has a different composition. The lithosphere
is the rigid outer layer that contains the crust and upper mantle.
The lithosphere is composed of three equally important
components, namely, inorganic (rocks and mineral), organic
(soil and fossil fuel), and biological (flora and fauna). Our
focus for this chapter and activity is on inorganic components.
Chemical Weathering
Rocks and mineral are all around us. Watch this video to
understand the difference between rocks and minerals.
Weathering describes the breaking down or dissolving of rocks
and minerals on the surface of the Earth. Water, ice, acids,
salts, plants, animals, and changes in temperature are all agents
of weathering. Weathering wears away exposed surfaces over
time. Chemical weathering occurs at a second stage of rock

2. disintegration in which small pieces of rock produced by
physical weathering are then further broken apart by chemical
processes such acid reactions, hydrolysis and oxidation.
Acid rain is formed when certain pollutants dissolve in rain
creating stronger acids. Learn more about acid rain here. Acid
rain is one factor that can increase the rate of erosion, with
effects that can be seen in just a few decades. Limestone and
marble are composed calcium carbonate, the same material as
chalk, and are commonly used for constructing buildings and
statues. Rain that is too acidic will “eat away” at these
structures very quickly.
Acids in rain such as sulfuric acid (H2SO4) dissolves the
calcium carbonate to make a moderately soluble form of
calcium, CaSO4 (called gypsum), along with carbon dioxide and
water. This is an acid-base neutralization.
This could also have positive impact: the regions where the
bedrock or soil contain large amounts of limestone are less
likely to have polluted water due to acid rain than areas with
igneous bedrock. This is because the limestone (which is a base)
is able to neutralize acid rain before it gets into the lakes and
rivers. This means that damage due to acid rain depends on both
the pH (amount of acid in a substance) of the rain and the type
of soil/bedrock.
In this activity, you will explore the effect of acetic acid (found
in vinegar) and lemon juice on chalk. You can also repeat this
activity with other rocks (if available) and record your
observations.
Procedure
Prepare three clear plastic cups and label them as water (W),
vinegar (V), and lemon juice (L). Add about 20 ml of each

3. liquid into these cups respectively.
Crush Break chalk into approximately three 1/2 cm pieces.
Crush each 1/2 cm piece of chalk into smaller pieces, keeping
each crushed 1/2 cm portion separate from each other.
Crush the first piece into smaller pieces and add to the cup
containing water. Observe the changes that take place. Record
your observations the data table.
Repeat with second piece of chalk and add to the cup containing
vinegar. Record your observations. Take a picture.
Repeat with third piece of chalk and add to the cup containing
lemon juice. Record your observations. Take a picture.
Look and listen carefully each time you add the chalk pieces to
these liquids.
This is optional: You can also repeat the activity with other
rock such as quartz or granite. You may not be able to break
those into smaller pieces though, but you can still try by taking
small pieces.
Credit: https://letstalkscience.ca/educational-resources/hands-
on-activities/what-are-effects-acid-rain-on-rocks
Name __________________
Pre-laboratory Assignment
1. What do you understand by the term weathering in the
context of this chapter?
2. Briefly describe the difference between minerals and rocks.

4. 3. What is an acid rain? List one positive and one negative
impact of the acid rain.
4. Which rock types are sensitive to acids?

5. Results
Record your observations in the following data table:
Water
Vinegar
Lemon Juice
Chalk
Granite (optional)
Limestone or quartz (optional)
Questions
1. Did the water and vinegar act the same way on chalk?
2. What type of reaction is occurring between the chalk and
vinegar?
3. Write the chemical equation for the reaction between acetic
acid (C2H4O2) and limestone (CaCO3).

6. 4. Predict what could have happened if you added more chalk to
the vinegar? Explain your prediction in terms of above
neutralization reaction.
4
Lab #10
US Air quality Activity. Name: _________________________
Air quality can vary from day-to-day. Some agencies monitor
air quality levels on an hourly basis and will provide foreca sts
so that sensitive people can plan their day accordingly.
Go to http://www.pca.state.mn.us/, Scroll down a bit and you
will see a map of Minnesota indicating current air quality
measurements. Click this map. First, learn about some of the
pollutants used to calculate the air quality index. Click on
“about air quality data” on the right side of your screen.
· Read the sections called: “About the Air Quality Index” and
“Issuing air quality alerts”, and “factors that contribute to poor
air quality” Answer questions 1 - 3
· At the end of the reading, find the following three links to use
to answer questions 4-5.
· Air quality and health, Using AQI to reduce exposure to air
pollution, and What you can do about air pollution.
Questions to answer (1pt unless otherwise indicated)
1. List the five pollutants that are used to calculate the AQI (air
quality index) in Minnesota.

7. 2. What is an air pollution health alert?
3. Read the “factors that contribute to poor air quality” section.
List at least 4 different facts you learned in this section.
4. What are at least three health effects caused by air pollution?
5. What are at least two ways to minimize exposure to air
pollutants on days when levels are unhealthy or worse?
6. Now go back to the “Current Air Quality” page (with the map
of MN), click the back button on your browser to go back one
page or find the link at the top. Scroll down and look at the
current conditions listed under the map. (2pts)
a) What is the current AQI number for the Twin cities? _______
b) Which of the 5 pollutants is currently listed as the one being
used to determine the AQI? ______________________
c) What is the forecasted AQI for the Twin Cities over the next
few days?

8. 7. Go to https://airnow.gov/ and look at an AQI map of the
entire United States. Spend some time looking at the forecast
and current AQI maps. Find an area that has moderate or
greater concern (any area that is not green) and click on that
part of the map to bring up the regional display for the area you
selected. (2 pts)
a) What area of the United States did you select that has AQIs
of concern?
b) You should see a list of cities in the region you selected.
Choose a city with data and with AQI levels of concern and
click on that city name. What city did you select?
c) On the right side of the screen you should see the air quality
forecast and the current conditions for the city you selected.
What is the current AQI the city you selected? Which of the
five pollutants is being used to calculate the AQI (which is
highest)?
d) Based on what you learned in question 5 above and the types
of pollution of most concern, come up with a prediction about
the cause of the air pollution in the area you selected.

9. 2
Lab #12: Water
Purpose
In this activity you will learn about water treatment and water
hardness. In the first part of the lab you will view some videos
on water treatment and answer questions. In the second part of
the lab you will test for water hardness in your home.
Video 1: Twin Cities Waste Water Treatment video
https://www.youtube.com/watch?v=D1aABVbI4JE
Watch this 15 minute video on sewage treatment in the metro
area and answer the following questions:
1. What happened to St. Paul waste water prior to 1938? Why
did this become a problem?
2. What does MCES stand for and what do they do today?
3. Where does waste water go directly after you flush or use the
sink?
4. What percent of the Twin Cities metro area waste water does

10. the Metro plant treat?
5. In primary treatment, what is an example of “floatable”
material?
6. In secondary treatment, what does the brown color of the
wastewater come from?
7. What is the last stage of the treatment process?
8. How often are water samples taken and tested?
Video 2: Testing for water hardness in your home
https://www.youtube.com/watch?v=jDgSohKVLio
1. Using your text, what ions are usually present in hard water?
2. What are some problems that can occur if your water is too
hard?
3. Collect two water samples from your home. Obtain one
sample from the kitchen sink and another sample from the

11. bathroom sink. Test the water with dish soap as described in the
video. Take a picture of your water samples immediately after
shaking.
a. Describe what you see for your water sample from the
kitchen. How hard is the water?
b. Describe what you see for your water sample from the
bathroom. How hard is the water?
c. Do you know if your water is treated with a water softener?
Check your faucets to see if there is evidence of hard water
build-up. Do your observations match with what you determined
in parts (a) and (b)?