Acids and Bases

pH scale The pH scale is used to determine if a chemical is an acid or a base Measures the number of hydronium (H3O+) ions in a solution.

pH scale Runs from 0-14 For each increase of one unit, the number of H3O2+ ions increases by a factor of 10

Acids Chemicals where the pH is less than 7. The lower the number the stronger the acid. The lower the number the weaker the base. Contains high numbers of H3O2+ ions; fewer OH ions

Acids Methods for determination in lab Turns blue litmus paper red Turns phenolphthalein clear

Acids Methods for determination in daily situations Tastes sour Reacts with metals Reaction can be slow or fast.

Common Acids HCl –hydrochloric acid HBr – hydrobromic acid HI - Hydroiodic acid H2SO4 – sulfuric acid HNO3 –nitric acid H2CO3 – carbonic acid HC2H3O2 – acetic acid

Bases Bases have a pH of more than seven. The higher the pH the stronger the base. The higher the pH the weaker the acid Contains many OH- ions; few H3O+ ions

Bases Tests for determining pH of bases in lab settings Turns red litmus paper blue Turns phenophthalein red

Bases Determination of pH in daily life: Bases taste bitter. Bases have a slippery feel. Soaps are basic and have a distinctive feel of a slippery base.

Common Bases LiOH –lithium hydroxide NaOH – sodium hydroxide KOH – potassium hydroxide RbOH –rubidium hydroxide Be(OH)2 – beryllium hydroxide Mg(OH)2 – Magnesium hydroxide Ca(OH)2 – calcium hydroxide Sr(OH)2 – Strontium hydroxide

Neutral Chemicals that have a pH of 7 OR Chemicals that do not affect H3O2+ or OH- concentrations.