Geography M2 Chemical Weathering

WHAT IS CHEMICAL

WEATHERING?

WHAT IS CHEMICAL

WEATHERING?

1 - OXIDATION1 - OXIDATION

2 - SOLUTION 2 - SOLUTION

3 - CARBONATION

3 - CARBONATION

4 - BIOTIC4 - BIOTIC

QUIZQUIZ

OBJECTIVESOBJECTIVES

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Geography Module # 2 Unit #1 Lesson #2

BEGINBEGIN

WHAT IS CHEMICAL

WEATHERING?

WHAT IS CHEMICAL

WEATHERING?



3 - CARBONATION

3 - CARBONATION


QUIZQUIZ

OBJECTIVESOBJECTIVES Students should be able to:

• define the terms chemical and biotic weathering,

• explain the processes of chemical weathering such as carbonation, oxidation and solution,

• discuss how different processes of chemical weathering are influenced by factors such as climate, rock type, and living organisms,

• understand the impact of chemical weathering on rock surfaces.

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WHAT IS CHEMICAL

WEATHERING?

WHAT IS CHEMICAL

WEATHERING?



3 - CARBONATION

3 - CARBONATION


QUIZQUIZ

OBJECTIVESOBJECTIVES Chemical Weathering is the decay of rocks. It occurs when rock minerals react with rain water, moisture or air to alter the chemical composition and structure of the rock. The original rock minerals are changed to form new compounds which leads to the decomposition of the rocks.

Types of chemical weathering are:Oxidation SolutionCarbonationBiotic

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WHAT IS CHEMICAL

WEATHERING?

WHAT IS CHEMICAL

WEATHERING?



3 - CARBONATION

3 - CARBONATION


QUIZQUIZ


WEATHERINGWEATHERING

Chemical WeatheringChemical Weathering

Oxidation Oxidation Solution Solution CarbonationCarbonationBioticBiotic

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WHAT IS CHEMICAL

WEATHERING?

WHAT IS CHEMICAL

WEATHERING?



3 - CARBONATION

3 - CARBONATION


QUIZQUIZ

OBJECTIVESOBJECTIVES Chemical Weathering

What you need: lemon or lime juice, vinegar, medicine droppers, two pieces each of limestone, chalk, and quartzite.

What to do: 1. Put a few drops of lemon juice on one of

each of the three rock samples. 2. Put a few drops of vinegar on each of

the other three samples. 3. Look and listen carefully each time you

add the lemon juice or 1the vinegar.

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WHAT IS CHEMICAL

WEATHERING?

WHAT IS CHEMICAL

WEATHERING?



3 - CARBONATION

3 - CARBONATION


QUIZQUIZ

OBJECTIVESOBJECTIVES Think about the questions and type your responses below. You must be in Slide Show view to type and delete text.

7Click for FeedbackClick for Feedback

WHAT IS CHEMICAL

WEATHERING?

WHAT IS CHEMICAL

WEATHERING?



3 - CARBONATION

3 - CARBONATION


QUIZQUIZ

OBJECTIVESOBJECTIVES What should have happened: • Lemon juice and vinegar are both

weak acids. These mild acids can dissolve rocks that contain calcium carbonate.

• The lemon juice and vinegar should have bubbled or fizzed on the limestone and chalk, which all contain calcium carbonate.

• There should not have been a reaction on the quartz, which does not contain calcium carbonate.

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WHAT IS CHEMICAL

WEATHERING?

WHAT IS CHEMICAL

WEATHERING?



3 - CARBONATION

3 - CARBONATION


QUIZQUIZ

OBJECTIVESOBJECTIVES • Oxidation is the process in which oxygen chemically combines with other substances.

• Oxidation occurs when rocks are exposed to oxygen the air or water. The chemical addition of oxygen to compounds in the rock can weaken the structure of the rock.

• When iron compounds combine with oxygen ferric oxide (iron oxide) is formed which gives rocks a reddish brown tinge.

• Oxidation causes rocks to decay and crumble easily.

• Oxidation is the process that causes metals to rust .

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WHAT IS CHEMICAL

WEATHERING?

WHAT IS CHEMICAL

WEATHERING?



3 - CARBONATION

3 - CARBONATION


QUIZQUIZ


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Can you identify the areas where oxidation has occurred?

In Slide Show view, type your answer in the box below.

WHAT IS CHEMICAL

WEATHERING?

WHAT IS CHEMICAL

WEATHERING?



3 - CARBONATION

3 - CARBONATION


QUIZQUIZ


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Describe what is taking place in the picture.In Slide Show view, type your answer in the box below.

WHAT IS CHEMICAL

WEATHERING?

WHAT IS CHEMICAL

WEATHERING?



3 - CARBONATION

3 - CARBONATION


QUIZQUIZ

OBJECTIVESOBJECTIVES Rocks that dissolve easily in water are said to be soluble.

Many minerals are soluble in water especially if the water is acidic. Minerals such as rock salt can be dissolved by water.

Most rain water and water in the soil are slightly acid. When the minerals in rock dissolve hollows are left within the rock structure while the less soluble minerals remain.

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WHAT IS CHEMICAL

WEATHERING?

WHAT IS CHEMICAL

WEATHERING?



3 - CARBONATION

3 - CARBONATION


QUIZQUIZ

OBJECTIVESOBJECTIVES • Carbonation is a form of chemical weathering which affects limestone. It operates like this:

• Carbonation takes place when carbon dioxide in the atmosphere dissolves in rain water to form carbonic acid.

• Rain water as a weak acid reacts with limestone (calcium carbonate) and it becomes soluble and dissolves in the water.

• The process of carbonation occurs along the joins in the limestone and enlarge them.

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WHAT IS CHEMICAL

WEATHERING?

WHAT IS CHEMICAL

WEATHERING?



3 - CARBONATION

3 - CARBONATION


QUIZQUIZ


A limestone pavement – notice the grooves and ridges caused by solution of the limestone 14

WHAT IS CHEMICAL

WEATHERING?

WHAT IS CHEMICAL

WEATHERING?



3 - CARBONATION

3 - CARBONATION


QUIZQUIZ


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Lichens are plants that produce weak acids. These plants often grow on rocks. As they grow, the acids they produce seep into the rocks and dissolve some of the minerals resulting in chemical weathering.

WHAT IS CHEMICAL

WEATHERING?

WHAT IS CHEMICAL

WEATHERING?



3 - CARBONATION

3 - CARBONATION


QUIZQUIZ

OBJECTIVESOBJECTIVES Are you ready to test yourself? There are four multiple choice items

that you are required to do. For each item, click on the letter of

the correct response and then click the button ‘NEXT QUESTION’ to continue.

You must be in sldie show view to do the quiz.

Click the BEGIN QUIZ button to proceed.

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BEGIN QUIZ!BEGIN QUIZ!

WHAT IS CHEMICAL

WEATHERING?

WHAT IS CHEMICAL

WEATHERING?



3 - CARBONATION

3 - CARBONATION


QUIZQUIZ

OBJECTIVESOBJECTIVES The general process by which rocks are broken down on the Earth’s surface is called:

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A. decomposition A. decomposition

B. erosionB. erosion

C. denudationC. denudation

D. weatheringD. weathering

FEEDBACKFEEDBACKFEEDBACKFEEDBACK

WHAT IS CHEMICAL

WEATHERING?

WHAT IS CHEMICAL

WEATHERING?



3 - CARBONATION

3 - CARBONATION


QUIZQUIZ

OBJECTIVESOBJECTIVES Question 1: The general process by which rocks are broken down on the Earth’s surface is called:

FeedbackWeathering is the first stage in the break down of rocks which are then picked up by agents of erosion such as running water, the sea and moving ice. All these processes result in denudation.

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NEXT NEXT QUESTIONQUESTION


WHAT IS CHEMICAL

WEATHERING?

WHAT IS CHEMICAL

WEATHERING?



3 - CARBONATION

3 - CARBONATION


QUIZQUIZ

OBJECTIVESOBJECTIVES The decomposition of rock from exposure to water and atmospheric gases is known as:

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A. Mechanical weathering A. Mechanical weathering

D. Salt wedging D. Salt wedging

C. Denudation C. Denudation

B. Chemical weatheringB. Chemical weathering


WHAT IS CHEMICAL

WEATHERING?

WHAT IS CHEMICAL

WEATHERING?



3 - CARBONATION

3 - CARBONATION


QUIZQUIZ

OBJECTIVESOBJECTIVES Question 2: The decomposition of rock from exposure to water and atmospheric gases is known as:

FeedbackChemical weathering results in the change in the chemical composition of rocks this is brought about by chemical reactions that occur in the presence of oxygen and carbon dioxide.

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WHAT IS CHEMICAL

WEATHERING?

WHAT IS CHEMICAL

WEATHERING?



3 - CARBONATION

3 - CARBONATION


QUIZQUIZ

OBJECTIVESOBJECTIVES Chemical weathering takes place most effectively when it is:

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A. Cold and dryA. Cold and dry

D. Dry all the timeD. Dry all the time

B. Cold and wetB. Cold and wet

C. Warm and wetC. Warm and wet


WHAT IS CHEMICAL

WEATHERING?

WHAT IS CHEMICAL

WEATHERING?



3 - CARBONATION

3 - CARBONATION


QUIZQUIZ

OBJECTIVESOBJECTIVES Question 3: Chemical weathering takes place most effectively when it is:

FeedbackChemical weathering occurs because

chemical reactions are occurring on rock surfaces. Most chemical reactions occur in the presence of water and in warm temperatures. Thus warm wet conditions are ideal settings for chemical weathering.

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WHAT IS CHEMICAL

WEATHERING?

WHAT IS CHEMICAL

WEATHERING?



3 - CARBONATION

3 - CARBONATION


QUIZQUIZ

OBJECTIVESOBJECTIVES Carbonic acid, the primary agent of chemical weathering is produced by:

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A. Plant rootsA. Plant roots

D. Oxygen reacting with iron compoundsD. Oxygen reacting with iron compounds

C. Bacteria that feeds on plant and animal remainsC. Bacteria that feeds on plant and animal remains

B. Carbon dioxide dissolving in rain waterB. Carbon dioxide dissolving in rain water


WHAT IS CHEMICAL

WEATHERING?

WHAT IS CHEMICAL

WEATHERING?



3 - CARBONATION

3 - CARBONATION


QUIZQUIZ

OBJECTIVESOBJECTIVES Question 4: Carbonic acid, the primary agent of chemical weathering is produced by:FeedbackRain water dissolves carbon dioxide from the air as it passes through it rain water (H2O ) + carbon dioxide (CO2) = mild carbonic acid (H2 CO3)

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WHAT IS CHEMICAL

WEATHERING?

WHAT IS CHEMICAL

WEATHERING?



3 - CARBONATION

3 - CARBONATION


QUIZQUIZ

OBJECTIVESOBJECTIVES The process in which oxygen chemically combines with substances is:

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B. Decomposition B. Decomposition

D. Denudation D. Denudation

C. Carbonation C. Carbonation

A. Oxidation A. Oxidation


WHAT IS CHEMICAL

WEATHERING?

WHAT IS CHEMICAL

WEATHERING?



3 - CARBONATION

3 - CARBONATION


QUIZQUIZ

OBJECTIVESOBJECTIVES Question 5: The process in which oxygen chemically combines with substances is:

FeedbackOxidation –is the chemical addition of oxygen to compounds in rocks and it can weaken the structure of rocks. Oxygen either dissolved in water or in the air combines with minerals present in the rocks. This type of weathering is also known as rusting as the rock discolours to a reddish-brown colour.

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END OF END OF QUIZ QUIZ

END OF END OF QUIZ QUIZ

WHAT IS CHEMICAL

WEATHERING?

WHAT IS CHEMICAL

WEATHERING?



3 - CARBONATION

3 - CARBONATION


QUIZQUIZ

OBJECTIVESOBJECTIVES You have reached the end of the quiz. If you wish to review this lesson, go to

the first slide. If you have finished viewing the

lesson, click the Close (X) button.

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Education

Geography M2 Chemical Weathering