Quiz 4.9 - Acid Lab Study Guide

Study Guide

Basic Info

Gases dissolved in our atmosphere: CO2, sulfur dioxide, hydrogen chloride = create an acidic solution


Carbonic acid --> dissolved CO2

Sulfur Dioxide --> "acid rain"

|--> volcanoes + industrial pollution + geysers


Acid rain kills forests + pollutes water (river, lake, pond)


Limestone/ Sinkholes


Limestone:

-porous (holds H2O)

-soft

-soluble in H2O (carbonic acid)


FL Sinkholes occur b/c:

- lots of limestone

- water underground (aquafer)

-once covered w/ocean--> soft calcium deposits (dead animals)


Sulfuric Acid

-Discovered in 8th century by alchemists --> alchemy "chemistry"


Uses

- lead acid batteries (cars)

- fertilizers

- steel industry --> prevents rust corrosion

- dried fruit production (hydrotropic)

Two Gases Post Lab

- Magnesium + carbonic acid: CO2 is a dense gas and it sinks


- Magnesium + acid: Hydrogen is a light gas and it rises


POP Sound

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


Experimental Errors

- not waiting 30 sec --> gas has to leave one test tube

- unstopper before inverting

- break surface H2O w/test tube

- don't collect full test tube of gas

- air bubble in test tube

- stoppers not tight

- not keeping test tubes vertical

Acidification Post Lab

- Phenol red changes color as you add CO2 into H2O

- The CO2 turns to carbonic acid lowering the pH of the H2O

- Calcium tablet is more soluble in cup w/straw

- B/c the carbonic acid lowers pH + dissolves calcium faster


Experimental Errors


- Don't bubble H2O long enough (not enough CO2)

- 2 cups don't have same amount of H2O

- Lose water when using straw

- Put CO2 into both cups