Slide 1

pH Scale AN INTRODUCTION

Slide 2

The pH Scale measures the strength of an acid or a base (alkaline) in solution

Slide 3

Lets review the characteristics of acids and bases (alkalines): Acids Taste sour (think lemons) React with some metals to give off hydrogen gas Turn blue litmus indicator paper red Neutralize bases to produce a salt and water Give off or donate H+ ( hydrogen ions) Bases Taste bitter, but most are toxic to humans (think cleaning products) Feel slimy or slippery, like soap Turn red litmus indicator paper blue Neutralize acids to produce a salt and water Accept H+ (hydrogen ions)

Slide 4

We can use the PH Scale to add to our list of characteristics: Acids have a pH lower than 7 the lower the pH number the stronger the acid Bases have a pH higher than 7 the higher the pH number the stronger the base Distilled water is neutral with a pH of 7

Slide 5

Keeping the characteristics of acids and bases in mind, what do you think pH stands for in the pH Scale? Proven Hypothesis? Try again! Possibly Harmful? Nope Heres a hint H+ YES! pH stands for potential Hydrogen!

Slide 6

Take a look at where these familiar acids and bases belong on the pH Scale:

Slide 7

Please read the directions in the orange boxes and then click on the central image to activate this science simulation. Experiment until you can answer the following question: What is the pH of.5 Liter of battery acid after you dilute it with.5 Liter of water? Record your answer on an index card it will be tomorrows ticket in the door! Add water to your solution with the blue knob Choose an everyday liquid from the drop down list Use the dropper to add more of your liquid Empty the beaker here to start over Drag the probe into your solution to measure the pH

Slide 8

In closing, enjoy this music video while you ponder the following questions for tomorrows discussion. If you spilled ammonia on your arm would you wash it off with soap? Why or why not? Tums has a pH of 8.5 and gastric (stomach) acid has a pH ranging from 1.5 to 3.5 when we eat Tums what (2 things)does some of our gastric acid turn into? Should chemists make music videos?

Slide 9

References Blais,T. (2014, Nov. 6 th ). All about that base (no acid). Retrieved from: https://www.youtube.com/watch?v=IAJsZWhj6GI pH Scale: Basics simulation : PhET Interactive Simulations University of Colorado http://phet.colorado.edu. http://phet.colorado.edu