Acids, Bases, Acids, Bases, and the and the

pH scale pH scale

AcidsAcidspH of 0 - pH of 0 - <<77React with metals and React with metals and BasesBases

Tend to taste sourTend to taste sourGive off/ contribute HGive off/ contribute H++ ions ions into a solutioninto a solution

Ex.) HCl Ex.) HCl HH++(aq)(aq) + Cl + Cl--

(aq)(aq)

(aq) stands for aqueous, which means it (aq) stands for aqueous, which means it is a solution in which the solvent is is a solution in which the solvent is water water (dissolved in water)(dissolved in water)

Acids…Acids…

There is a very strong acid in our There is a very strong acid in our stomach, HCl. This is what stomach, HCl. This is what sometimes cause heartburn.sometimes cause heartburn.

BasesBasespH of >7 - 14pH of >7 - 14Do not react with metalsDo not react with metalsReact with acidsReact with acidsTend to taste bitterTend to taste bitterGive off/ contribute Give off/ contribute hydroxide ionshydroxide ions ( ( OHOH-- )to a )to a solutionsolution

ex.) NaOH ex.) NaOH Na Na++(aq)(aq) + + OHOH--

(aq)(aq)

NeutralNeutral

NeutralizatioNeutralizationn

pH of 7pH of 7 Neither acidic nor basicNeither acidic nor basic Pure waterPure water

We can neutralize an acid We can neutralize an acid with a base, or neutralize with a base, or neutralize a base with an acid.a base with an acid.

Ex.) There are bases secreted in Ex.) There are bases secreted in our intestines that neutralize the our intestines that neutralize the acid from our stomach.acid from our stomach.

The pH ScaleThe pH Scale A scale developed in order A scale developed in order

to determine how acidic or to determine how acidic or basic a substance is.basic a substance is.

Values on the scale range Values on the scale range from 0-14.from 0-14.

IndicatorIndicator A substance that A substance that

changes color in the changes color in the presence of an acid or presence of an acid or base.base.

Ex. Cabbage Juice, litmus Ex. Cabbage Juice, litmus paperpaper

The pH Scale…The pH Scale…