pH: Another Chemical Property

Let’s talk about water. 70% of Earth is covered in water 100% of living things have water in them Water is a necessity of life

+ + H H O _

Water Dissociates constantly Breaks apart 2 pieces: Hydroxide Ion Hydrogen Ion + H+ Water OH-

H+ vs. OH- Pure water: H+ = OH- Acids: H+ > OH- Bases H+ < OH-

pH Scale Measures the strength of acids and bases How much H+ is in a substance Created in early 1920 by Soren Sorenson To help the beer brewing industry Hydrogen Potential

pH Scale Range is 0-14 Each step is a 10X difference Fresh water

Acids vs. Bases: Bases Acids Anything less than a 7.0 More H+ ions The more H+ ions the stronger the acid Taste sour Corrosive To metals and living things Turn litmus paper Red Examples: HCl, fruits, sodas, battery acids Anything more than 7.0 More OH- ions The more OH-, the stronger the base Taste bitter, chalky Cause burns Turns litmus paper blue Examples: Soaps, cleaners, ammonia

Determining pH: Indicators: Change colors when acids or base is added Examples: pH paper Litmus paper Red cabbage

Combining Acids and Bases: Neutralization Reaction Brings mixture’s pH to 7.0 Ex. pH 3 added to pH 11 will lead to 7.0 Forms Salts and water + Salt

Combining Acids and Bases: In you: Stomach pH is 4.5 After eating drops to a 1-2 Can cause indigestion Antacids Raise pH up to normal HOW?

Acids Bases

1 2 3 4 5 6 Baking Soda Tap Water Table Cleaner Ammonia Lemon Juice Soda Vinegar coffee Egg Saliva