1. Acid and Base Chemistry

2. The Use of Hydrochloric Acid (HCl)
Is excreted by the stomach lining and acts to:
weaken the bonds holding the food together
dissolve minerals from various foods
kill bacteria which enter our stomach with the food we eat.

3. pH Is a measure of how acidic a substance is
Acid examples  Hydrochloric acid, Sulfuric Acid, Citric Acid
It is measured on a scale (pH scale) from 1-14
7 (Neutral) = Water and Blood
< 7 (Acidic) = e.g. Vinegar
> 7 (Basic) = e.g. Ammonia (household cleaner)

4. Acids Release hydrogen/hydronium ions in water (H+/H3O+)
Ex. HCl(aq)  H+(aq) + Cl-(aq)
Balanced because 1 H on the left and right & 1 Cl on the left and right
pH < 7
Sour-Tasting
Reactive (explosive, corrosive  Handle with Care)

5. Acids Act as preservatives keeping food good longer
Kills microorganisms that make food go bad
HCl(aq) + Zn(s)  H2(g) + ZnCl2(aq)
React with metals to produce Hydrogen
Hydrogen is highly combustible!!

6. Acids Conduct Electricity
Although they are molecular compounds, when placed in water they collide with water, breaking the acid into ions. These ions are used to conduct electricity
HCl  H+ + Cl-
You will notice that the chemical formula for acids start with an H and are followed by an aq.
** The H+ is responsible for the acids properties**
Examples: Vinegar, Citric Acid, Lactic Acid

7. Common Acids Binary Acids – Composed of two elements
Acid Name
Chemical Formula
Use
Hydrofluoric Acid
HF(aq)
Etching glass
Hydrochloric Acid
HCl(aq)
Cleaning concrete
Common Oxyacids – Related to Polyatomics
Acid
Chemical Formula
Acetic Acid
HC2H3O2(aq)
Nitric Acid
HNO3(aq)

8. Acid Precipitation
Fossil fuels are made from dead organisms which have been buried underground for millions of years.
When fossil fuels (coal, oil, gas) are burned to make energy, nutrients are released which can form undesirable compounds
Nitrogen and Sulfur are released which combine with oxygen to form Nitrogen Oxides (NOx) and Sulfur Dioxide (SO2)
These then combine with Water (H2O) in the atmosphere to form acids (Nitric Acid - HNO3 & Sulfuric Acid – H2SO4)
These acids then fall to earth as acid precipitation in the form of rain, sleet or snow

9. Acid Precipitation

10. Effects of Acid Precipitation
Forest soils lose valuable nutrients killing plant life
Destroy stone work

11. Effects of Acid Precipitation
Can cause series problems in aquatic ecosystems killing fish, amphibians and other organisms due to a decrease in pH

12. Bases Release Hydroxide Ions in Water (OH-)
NaOH(s)  Na+(aq) + OH-(aq)
Your bases will contain an OH- (Hydroxide) as a reactant
pH > 7
Taste Bitter
Reactive (Corrosive)  Dangerous
Examples: Drain Cleaner, Soap, Antacids

13. Bases
Most Bases are Ionic Compounds and therefore dissolve in water into ions
Ba(OH)2(s)  Ba2+(aq) + 2OH-(aq)
Since ions are formed in water, bases will conduct electricity
Base Name
Chemical Formula
Use
Sodium Hydroxide
NaOH(aq)
Making paper
Calcium Hydroxide
Ca(OH)2(aq)
Decreasing acidity in lakes and soil

14. Acids and Bases Video

15. pH Is a measure of how acidic a substance is
7 (Neutral) = Water and Blood
< 7 (Acidic) = e.g. Vinegar
> 7 (Basic) = e.g. Ammonia (household cleaner)
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