Introduction to pH of Acids and Bases Tahoma Jr. High 8 th Grade Science Maple Valley, WA

pH (power of Hydrogen) pH is a measurement of the numbers of acid or base particles compared to water. The scale runs from 0 through 14. Water is in the middle of the scale – not being acid or base strong acid NEUTRAL strong base Indicators are used to tell us what the pH level of a substance is. weak acid weak base

pH test strips (AKA “Litmus Paper”) are chemically treated papers that change different colors depending on the pH of the material placed on the paper (you compare a paper’s color to the color on the box it came in) this would be a pH of 12 (some papers’ chemicals don’t produce green for neutral – you have to use their color scheme on the box – so don’t get your papers mixed up with other boxes!)

Another common way to test pH (especially with pools or hot tubs) is with liquid chemicals instead of treated paper. (you compare to the color scale on the tubes)

If the water is not within the correct/safe pH range, then you need to add chemicals to bring the water back into that range.

show 5 min TED - pH video

When equal amounts of acid ions are combined with an equal number of base ions, neutralization occurs. OH- H+ H2OH2O What will an ion of acid and an ion of base make when combined ?

The other ions from the acid and the base combine to create a salt. Na+ OH- H+ Cl- H+ H2OH2O NaCl (table salt) Cl- Na+ What chemical besides water is made when HCl and NaOH are combined ?

show 3 min pH in Body video

pH of common drinks (think what these are doing to your teeth enamel…) end show drinkpH Gatorade2.4 vinegar2.5 colas2.7 apple cider3.1 7-Up3.2 apple juice3.4 root beer4.0 Juicy Juice4.5 coffee5.5 milk6.5 soy milk7.0 water7.0 tea7.2 do you want to see what happens to teeth from too much soda – any soda, not just diet soda? (or meth?) – just click again Probably not a good idea to be “swishing” that soda around your mouth, eh? There’s phosphoric acid, carbolic acid (from the CO 2 ), citric acid… Colas are by far the WORST soda/juice (and very bad for your kidneys too). We teach you this chemistry to help you protect your body/health. Teeth health is closely connected to the health of other body parts. meth user diet soda