p in Prentice Hall Biology, Miller and Levine
What just happened with the witches and their pink potion?
Chemicals that respond to a change in H ion concentration Change color depending on whether substance is an acid or a base Examples: litmus paper phenolphthalein
What is an ion? Answer: positively or negatively charged atom
A compound that forms H + ions in a solution Example: Hydrochloric acid produced by stomach to digest food (HCl)
Contains Hydrogen (H+) Turns litmus paper red Tastes sour Dissolves metal
A compound that forms hydroxide ions (OH-) in a solution Example: Lye
Contains Hydroxide Turns litmus paper blue Tastes bitter Feels slippery
The pH scale What does pH stand for Power of Hydrogen Scale ranges from 0 to 14
Acids have a pH below 7 Strong acids range from 1 to 3 Strong acid example: HCl
Bases have a pH above 7 Strong bases range from 11 to 14 Strong base example: lye
pH increases tenfold
A water molecule can react to form ions
Why is pure water considered “neutral”? Pure water pH = 7 Number of positive hydrogen ions equal to negative hydroxide ions produced