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ACID RAIN. pH Warm-Up. What does pH scale measure? What pH value is considered “neutral”? Which pH values are “acidic”? Which pH values are “basic” or “alkaline”?. What is the pH of rain?. Pure water has a pH of 7 – neutral (neither an acid nor a base)
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pH Warm-Up • What does pH scale measure? • What pH value is considered “neutral”? • Which pH values are “acidic”? • Which pH values are “basic” or “alkaline”?
What is the pH of rain? • Pure water has a pH of 7 – neutral (neither an acid nor a base) • Normal precipitation is slightly acidic (5.6) because carbon dioxide in the air mixes with rain water to form a weak acid called carbonic acid. • H2O + CO2 H2CO3
How does acid precipitation form? Factories that burn fossil fuels release sulfur oxides and nitrous oxides Cars that burn fossil fuels release nitrous oxides
How does acid precipitation form? Sulfur and nitrous oxides combine with water in the atmosphere to form sulfuric acid and nitric acid H2O + SO2H2SO4 H2O + N2OxHNO3 These strong acids lower the pH of rain more than H2CO3
So where does it come from and where is it going? • Acid rain follows prevailing winds. • It starts in places where there are a lot of factories and ends up wherever the wind blows it • This means the people experiencing it aren’t necessarily the ones causing it • Non-point Source Pollution Prevailing Winds in N. America
What happens to the soil and water around us? Acidification of soils & water • Acid rain can cause a drop in the pH of soil and water - called acidification. Does this make the soil and water MORE or LESS acidic? • That’s right….MORE
Acid Precipitation and Humans • Toxic metals (aluminum and mercury) can be released into the environment when soil acidity increases. • These toxic metals get into crops, water, and fish. • The toxins then poison the humans who eat the crops, water and fish.
Acid Precipitation and Humans 2) Research has indicated that there may be a connection between large amounts of acid precipitation and an increase in respiratory problems in a community’s children
Acid Precipitation and Humans 3) Fisherman can’t fish because the number of fish is decreased because by acidification of lakes The Forestry industry is also affected because trees are damaged by acid precipitation.
Acid Precipitation and Humans 4) Acid precipitation can dissolve the calcium carbonate in common building materials, such as concrete. As a result, some of the worlds most important and historic monuments, including those made of marble are being affected.
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Acid Rain Lab • Part 1- “Dragon’s Breath”- GOGGLES PLEASE!!! • BtB: a pH indicator (blue yellow pH = 6) • Observe pH changes as you add CO2 through a straw (blowing bubbles) • Part 2- How does acid rain affect limestone? • Chalk will represent our limestone • 4 solutions to test- 1 full piece of chalk/solution • Distilled water (control) • 50/50 water and vinegar (NOT 10/90 solution as stated in pkt.) • 100% vinegar