Presentation on theme: "Introduction to pH of Acids and Bases Tahoma Jr. High 8 th Grade Science Maple Valley, WA."— Presentation transcript:
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 H+ ions in a solution (they are very reactive without their e - ), and thats why acids break things down. The scale runs from 0 (or 1) through 14. Water is made up of equal numbers of H+ and OH- ions and has a pH of 7 – or neutral. ( right in the middle of the scale ) 0 (or 1) 714 strong acid NEUTRAL strong base Indicators are used to tell us what the pH 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 to the color on the box) this would be a pH of 12 (some papers chemicals dont produce green for neutral – you have to use their color scheme on the box – so dont 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)
an acid is a substance which releases hydrogen ions when combined with water HCl (hydrochloric acid) H positive hydrogen ion negative chlorine ion Cl + -
the strength of an acid depends on how many hydrogen ions are dissolved in the water weaker acid stronger acid H+H+ H+H+ H+H+ H+ HOW MANY TIMES STRONGER IS THE STRONG ACID ?
the stronger acid is three times stronger than the weak acid because there are 3x as many hydrogen ions to do the work weaker acid stronger acid H+H+ H+H+ H+H+ H+
a base is a substance which releases hydroxide ions when combined with water NaOH (sodium hydroxide) Na positive sodium ion negative hydroxide ion OH + -
Which base below is the strongest ? OH- A B How much stronger ? Base A has twice as many OH- ions so it is twice as strong (2x)
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 ?
Neutralization Neutralization is when one H+ ion (acid) and one OH- ion (base) are combined. Complete neutralization occurs when there are the same number of H+ ions and OH- ions in a solution. This makes it neither an acid or a base. It would then have a pH of 7 (distilled/pure water).
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? Theres phosphoric acid, carbolic acid (from the CO 2 ), citric acid… Colas are by far the WORST soda/juice. (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