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Learn about pH in our daily life - from body organs to cleaning products. Discover how pH affects food, drinks, water quality, and ecosystem health. Understand the properties of acids and bases, the pH scale, and acid-base reactions.
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Environmental Science Lesson 6 - pH
Everyday pH • pH is both in and around us all the time • Body organs require certain pH to function • Food/drink • Some people are sensitive to acids • Colas, orange juice, coffee, etc. • Can remove calcium from bones in women • Cleaning products • Ammonia/bleach (pH over 11.5) • Hand soap (pH 9-10) • React better with proteins than metal
pH of Water • Water can have different pH values • Pure water: pH 7 • Acid rain: pH 5 or lower • Seawater: pH of 8 • Unpolluted lake/river: pH of 5-8 • However, a dramatic rise or drop could destroy a healthy ecosystem
Acids • An acid is a solution that has an excess of H+ ions. • The more H + ions, the more acidic the solution. • It comes from the Latin word acidus that means "sharp" or "sour". • Properties: • Tastes Sour • Conduct Electricity • Corrosive, which means they break down certain substances. Many acids can corrode fabric, skin,and paper • Some acids react strongly with metals • Turns blue litmus paper red
Bases • A base is a solution that has an excess of OH- ions. • Another word for base is alkali • Properties: • Feel Slippery • Taste Bitter • Corrosive • Can conduct electricity (Think alkaline batteries.) • Do not react with metals • Turns red litmus paper blue
The pH Scale • pHis a measure of how acidic or basic a solution is. • The pH scale ranges from 0 to 14. • Acidic solutions have pH values below 7 • A solution with a pH of 7 is neutral. • Pure water has a pH of 7. • Basic solutions have pH values above 7.
What’s the difference b/t pH levels? • A change of 1 pH unit represents a tenfold (x10) change in the solution. • For example, solution one has a pH of 1 and solution two has a pH of 2 • The first solution is not twice as acidic as the second—it is ten times more acidic.
Acid-Base Reactions • A reaction between an acid and a base is called neutralization. • An acid-base mixture is not as acidic or basic as the individual starting solutions.