End of Ch. 4 Quiz

4.9 Acid Rain

Gases dissolved in our atmosphere (they create an acidic solution)

  • CO2
  • sulfur
  • hydrogen chloride

Carbonic Acid-dissolved CO2

Sulfur Dioxide (volcanoes, industrial pollution)-"acid rain"

  • kill forest
  • pollute water (rivers, lakes, and ponds)

What does calcium carbonate do to water?

  • It makes it hard

Why can't the city publish a law that they can't distribute water with toxic substances?

  • There is always a low level of toxic substances in public water, so if the law was passed, then there would be no water.

Why are large deposits of sodium chloride/potassium nitrate found near deserts?

  • the desert was once an ocean

Limestone, Sinkholes & Sulfuric Acids


  • soft
  • porous (can hold a lot of water)
  • a lot of it in Florida
  • soluble in water (carbonic acid)

Florida sinkholes occur because:

  • lots of limestone
  • water underground in caves (aquifer)
  • once covered with ocean --> soft calcium deposits (dead animals)

Sulfuric Acid

  • discovered in 8th century by Alchemist (turns things into gold)
  • alchemy--> chemistry

Sulfuric Acid uses:

  • lead acid batteries (cars)
  • fertilizers
  • steel industry --> prevents rust corrosion
  • dried fruit production (hydrotropic)

Two Gases Lab

Magnesium Carbonate & Acid:

  • In the upright test tube, which is filled with CO2, the dense gas sinks and cannot escape. The flame goes out right away.
  • In the inverted test tube, which is now filled with air, the gas escapes. The flame stays lit.

Big image
Magnesium & Acid:

  • The light gas rises.
  • In the upright test tube, which is filled with air, the gas escapes. It made a popping noise. The flame goes out.
  • In the inverted test tube, which is filled with hydrogen, the gas cannot escape (why you wait 30 seconds. It made a popping noise.
Big image
The "POP":

  • The gas is ignited and rushes out of test tube.
  • Rubs against glass causes friction (sound)

Acidification of Water

Phenol Red:

  • pH indicator
  • red: basic
  • clear: acidic

Phenol red in water:

  • bright pink

with CO2 over water:

  • orange

with CO2 in water

  • yellow

  • phenol red changes color as you add CO2 into the water
  • the CO2 turns into carbonic acid lowering the ph of the water
  • calcium tablet is more soluble in cup with straw
  • because the carbonic acid lowers ph and dissolves calcium faster

Ocean Acidification

  • Normal Ocean pH is 8.1-8.4
  • Ocean's pH has decreased 0.1 (about 25% down)
  • Lower ocean pH means sea animals with shells will not be able to make a shell.