What is acidification?

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The World We CreateNATS 101Section 6
Please, turn in your homework!
03/09
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The World We Create
Although we may not have all of the evidence
needed to claim that human actions are inducing
global warming in our planet, there is clear
evidence that the pollutants we produce are
reshaping the face of our planet.

• Carbon Dioxide (CO2)
• Nitrogen Oxides (NOx)
• Sulfur Oxides (SO2,SO3)

How?
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Acidification Human-Made
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A Water World
Pollutants that react with water alter they
properties and can have a serious impact on life
in our planet.
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Water Properties
In pure water, for every 550,000,000 molecules of
H2O, we have 1 H3O ion and 1 OH- ion
There are many substances that react with water
and change the relative amount of H3O and OH-
ions in solution
H3O OH-
ACIDS Increase Decrease
BASES Decrease Increase
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Acids and Bases
Acids are substances that can react with water to
produce more hydronium ions H3O.
What acids do you know?
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pH Scale
? ACIDIC NEUTRAL BASIC ?
pH gt 7 Basic
pH lt 7 Acidic
Small pH changes ? Life or Death
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How can we determine the pH of a solution?
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How to Test for pH

• Litmus Paper
• Bromothymol Blue
• Phenolphthalein
• Boiled Red Cabbage

ACID-BASE INDICATORS
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CLEAR LIQUIDS DEMONSTRATION
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Class Experiment
Substance Approximate pH
Muriatic Acid 1
Lemon Juice 2
White Vinegar 3
Lemon-Lime Soda 4
Seltzer Water 5
Milk 6
Distilled water 7
Baking Soda in water 8
Antacids in water 9
Bleach 10
Ammonia 11
Lye 12

• You will have 6 unknown liquids to test
• Test each liquid for its pH, write down your
  results, and determine their identity.

• You have 10 minutes

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Discussion

• What did you observe?
• Which of the substances were acidic? Basic?
• What were the substances?
• What did you use besides pH to determine
  this?
• Why would we need to know this?

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Results
Trial Unknown liquid color code Color with indicator Estimated PH Acid or Base Strong or Weak Substance Hypothesis
1 C Pink 3 Strong acid White Vinegar
2 E Fushia 5 Acid Seltzer
3 A Purple 7 Neutral Distilled Water
4 F Blue 8 Weak Base Dissolved Baking Soda
5 B Clear Yellow 10 Strong Base Bleach
6 D Yellow 11 Strong Base Ammonia
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Investigating Pollutants
Pollutants such as CO2, NOx, SO2, and SO3 react
with water and change its pH. Lets investigate
it!
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Class Experiment

• Using your materials, determine the pH of a
  carbon dioxide solution
• Record what you find
• Write three potential implications of these
  results for water and life in our planet.

You have 5 minutes
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What happened?
What did you observe? Is CO2 acidic, basic, or
neutral? Why is this significant?

• When CO2 dissolves in water it forms carbonic
  acid
• CO2 H2O ? H2CO3
• H2CO3 H2O ? H3O HCO3-

What is the problem?
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Ocean Acidification
The average pH level of the ocean in the past
(1700s and earlier) has been 8.179 In recent
times the average pH of for the entire ocean has
fallen to 8.104 (DpH -0.075)
30 increased acidity.
Oceans have absorbed 50 of all our emission.
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The ENTIRE Ocean
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Effects
The rate of CaCO3 production by coral has
decreased 6-11 since pre-industrial times.
Higher T ? Higher Rate
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Acid Rain

• Acid rain rain with pH lower than 5.6.

• Primarily caused by sulphur dioxide (SO2) and
  nitrous oxides (NOx NO, NO2, N2O)

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Effects
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The US What do you see?
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Clean Air Act
In 1995, Phase one of the Clean Air Act
Amendments of 1990 took effect for 110 electrical
utilities. Most of these power plants were in
the Eastern US.
Larger impact
NOx
SO2
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Project 2 available in D2L!
Due Tuesday March 23, 200 PM.
TWO MAJOR PREPARATION ACTIVITIES TODAY Work in
your groups addressing major misunderstandings. TH
URSDAYIn class activities to reinforce ideas
and help you assess your understanding.Begin
work on one project question.