Acids and Bases & The pH Scale

Brain Pop: pH Scale http://www.brainpop.com/science/matterandchemistry/phscale/

Acids and Bases When we think of acids and bases we tend to think of science labs and chemicals….but did you know…… Acids cause: Lemons to be sour Acid rain to eat away at sculptures Framed painting to be damaged Cavities in your teeth Food to digest in your stomach Ants and bees use it to sting!

Acids and Bases

Properties of Acids and Bases Tastes sour Acids corrode metals Positively charged hydrogen ions (H+) Taste bitter Feel slippery Most hand soaps and drain cleaners are bases Negatively charged hydroxide ions (OH-)

pH Scale Neutral 7 Acid Base 14 14 pH Scale Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 515

Understanding the pH Scale pH stands for: Presence of Hydrogen Numbered from 0 to 14 The lower the pH number the higher the Acid that means more hydrogen ions (H+) The higher the pH number the higher the Base that means less hydrogen ions (H+)

Common Acids Hydrochloric Acid Citric Acid Lactic Acid Stomach acid: has the sour taste of acid Citric Acid Citrus fruits such as lemons, grapefruit, oranges and limes Lactic Acid Sour milk, sour cream, yogurt and cottage cheese.

Common Bases Ammonia -Used in household cleaning materials and fertilizer. **Most Common!** Calcium hydroxide -Used to make mortar and plaster Sodium hydroxide Used in oven and drain cleaners **One of the strongest bases**

Virtual Lab What is the pH of common solutions? http://www.glencoe.com/sites/common_assets/science/virtual_labs/E22/E22.html