Acids and Bases

Chapter 15

Acids

• a substance which when added to water produces hydrogen ions (H+)

• hydronium (H3O+) is created

Water + Hydrogen ion = hydronium

H2O + H+ = (H3O+)

Properties of

• sour taste (lemons, vinegar)

• reacts with metals to produce hydrogen gas

• corrosive, destroys metals, burns skin

Acids

Uses of

• separate metals from their ores

• sulfuric acid – fertilizers

• hydrochloric acid – your stomach for digestion

• carbonic acid and phosphoric acid – sodas taste

Acids

Bases

• a substance which when added to water produces hydroxide ions (OH-)

Sodium Hydroxide (in water) = Sodium ion + Hydroxide Ion

NaOH = Na+ + (OH-)

Properties of

• bitter taste

• feels slippery, like soap

• corrosive, destroys metals, burns skin

Base

Uses of

• sodium hydroxide – soap

• cleaning products – ammonia, detergents

• calcium hydroxide – plaster, cement

• magnesium hydroxide – antacids for heartburn

• sodium bicarbonate – baking soda

Base

Indicators• Litmus paper

Color Blue Litmus Red LitmusAcid turns red stays redBase stays same turns blue

way to remember

Base turns Blue

Indicators• Liquids– thymol blue– methyl yellow– methyl orange– bromphenol blue– bromcresol green– methyl red

– bromthymol blue– phenol red– alizarin yellow– cresol red– thymolphthalein– Phenolphthalein

• Red cabbage juice is a commonly used indicator.• Liquids change different color in the presence of

acids and bases.

Neutralization

• When an acid mixes with a base, water is formed.

Why?

hydrogen ion + hyroxide ion = water

(H+) + OH– = H20

• The left over stuff makes salts.

Neutralization

Strength of acids and Bases

• Strong acids create a lot of hydrogen ions.• Strong bases create a lot of hydroxide ions.

• Determined by pH Scale

pH – measure of the concentration of hydronium ions in a solution

• How to measure

pH paper – changes color based on strength of acid or base

pH scale

• range from 0 to 14• more acidic = lower number• more basic = higher number• Acids and Bases

stronger acid stronger base

Sites

• Sugar and Sulfuric Acid

• Sulfuric Acid