1. pH Scale and neutralization

2. Learning goals We are learning to use acid-base indicators.
We are learning to predict the reactants and products of neutralization reactions.

3. pH Scale
pH: A measure of how acidic or basic (alkaline) a solution is.
The pH scale is a numerical scale ranging from 0-14 that compares the acidity of solutions.
: Acidic
7: Neutral (neither acidic or basic)
: Basic

4. Substance pH Acidic or basic?
Some examples:
Substance pH
Acidic or basic?
Milk 6
Baking soda
8.3
Tomatoes 4
Bleach 12
Stomach acid
1.5
Draino 13
Acidic
Basic

5. Impact of pH Farming Consumer Products Swimming Pools
pH of soil highly impacts which plants can grow in certain areas and which cannot.
i.e: Corn prefers slightly acidic soil, beans prefer slightly basic.
Consumer Products
Most skin care and shampoo products are neutral (pH=7)
Cleaners are usually highly basic and have HHPS symbols to indicate it.
Swimming Pools
To keep biologic organisms from growing pH needs to be between
Anything above / below can cause irritation to skin & eyes.

6. Neutralization Reactions
Occur between an acid and a base.
Both are typically ionic compounds.
Skeleton equation:
Acid + Base  Water + Salt (ionic compound)
Using hydrochloric acid and sodium hydroxide (base):
HCl(aq) + NaOH(aq)  H2O(aq) + NaCl(aq)

7. CaCO3 + 2HCl -> CO2 + H2O + CaCl2
Antacids
Your stomach produces a solution of hydrochloric acid (pH = 1.5)
Stomach acid can lead to irritation (heartburn) of the stomach lining and lining of the esophagus.
Antacids are designed to neutralize the acid.
Tums (Calcium carbonate) and stomach acid:
CaCO3 + 2HCl -> CO2 + H2O + CaCl2

8. Learning goals We are learning to use acid-base indicators.
We are learning to predict the reactants and products of neutralization reactions.

9. Homework
P.275 #2-4,6
P.281 #1,2,7
Neutralization funsheet