Science Study Guide for quiz

Acidification Lab and 4.9- Two Gases Lab

FREA'S: page 92 #'s 36, 37, 39-43, and 45

Two Gases: (Post- Lab)

Magnesium Carbonate and Acid(Carbon Dioxide):


  1. Dense gas sinks right side up: can't escape upside down: gas escapes


Magnesium and Acid(Hydrogen):


  1. Light gas rise ^ right side up: gas escapes upside down: can't escape
  2. The "Pop" (upside down test tube) was gas igniting and rushing out of the test tube. It rubbed against the glass causing friction (sound)


Errors:


  • Not waiting 30 seconds
  • Unstoppering before inverting
  • Break surface water with test tube
  • Don't collect full test tube of gas
  • Air bubble in test tube
  • Stopper not tight
  • Not keeping test tubes vertical

Acidification Lab: (Post- Lab)

Notes:


  • Phenol red changes color as you add carbon dioxide into the water
  • The carbon dioxide turns to 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


Errors:


  • Don't bubble water long enough (not enough carbon dioxide)
  • 2 cups don't have same amount of water
  • Lose water when using straw
  • Put carbon dioxide into both cups


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 (crabs, shrimp, clams, etc.)

Limestone/sinkholes: (Notes)

Limestone:


  • porous(holds water)
  • soft
  • soluble in water (carbonic acid- dissolved carbon dioxide)


Florida Sinkholes occur because:


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

Sulfuric Acid: (Notes)

  • Discovered in eighth century by alchemist--> alchemy "chemistry"


Sulfuric Acid Uses:


  • lead acid battery(cars)
  • fertilizers
  • steel industry- prevents rust corrosion
  • dired fruit production (hydrotropic)