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):
- Dense gas sinks right side up: can't escape upside down: gas escapes
Magnesium and Acid(Hydrogen):
- Light gas rise ^ right side up: gas escapes upside down: can't escape
- 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)