If the number of H + ions in a solution is greater than number of OH - ions, the solution is an acid If the OH - ions are greater than the H + ions, the solution is a base
Indicates hydrogen ion (H+) concentration Ranges from 0-14 Acids are found in the 0-6 range Bases are found in the 8-14 range 7 is NEUTRAL!! 1 2 3 4 5 6 7 8 9 10 11 12 13 14 strongest acid neutral strongest base
pH 0 to pH 14 H+ DECREASES As you move from pH 0 to pH 14, the concentration of H+ DECREASES (10 times each number) pH 0 to pH 14 OH- INCREASES As you move from pH 0 to pH 14, the concentration of OH- INCREASES (10 times each number)
1. As you move from pH 7 to pH 4 what happens to H+ concentration? 2. As you move from pH 2 to pH 8 what happens to OH- concentration? 3. How much more acidic is a solution with a pH 1 vs. pH 5?
Neutralize acids and bases Keep the pH from undergoing large changes
Practice: Read the entire article. Write the main point for each paragraph under the paragraph. Lab: Make a prediction for each substance. Move around to each station and dip the pH paper into the solution. Use the scale to determine the pH of each substance.
1. Which solution was the strongest acid? The strongest base? 2. Which solution was the weakest acid? The weakest base? 3. Did you predict that any solution would be neutral? Was your prediction correct? Explain. 4. How many of your predictions were confirmed during the lab? Explain.