BASESACIDS

· Identify acids and bases based on their pH.

· Understand and balance a Neutralization reaction.

pHNeutralNeutralization

Key Words

When dissolved in water, A/B dissociate to ions.

HNO3 (s) (aq) + NO3-

(aq)H+

Hydrogen ion is responsible for acid properties.

Ca(OH)2 (s) Ca+2 (aq) + 2

(aq)OH-

Hydroxide ion is responsible for base properties.

Measuring the Strength of Acids and Bases

The strength of an acid or a base is measured using the pH scale.

acidic pH 0 - 6.9low numbers mean strong acid, higher numbers mean weak acid.

basic pH 7.1 - 14 low numbers means weak base, higher numbers means strong base.

pH 7: neutral - not acidic, not basic.

Determine whether the substance is neutral, a weak or strong acid, or a weak or strong base.

Acid or base pHStomach fluid 1.7 STRONG ACIDLemon juice 2.6 Vinegar 2.8 Soft drinks 3.0 Oranges 3.5 Milk 6.5 WEAK ACID

Pure water 7.0 NEUTRAL

Blood 7.4 WEAK BASESea water 7.8 Ammonia (NH3) 11.0Lye (NaOH) 14 .0 STRONG BASE

Acids and base at home

1. Citrus fruit (citric acid)

2. Vinegar (acetic acid)

3. Special cells in the stomach produce a very strong acid - hydrochloric acid (HCl).

1. Window cleaner (ammonium hydroxide) NH4OH

2. Drain (potassium hydroxide - lye) KOH

3. Antacids (calcium hydroxide) Ca(OH)2

Neutralizes stomach acid.

Neutralizatio

n Reactions

Neutralization reaction:Mixing acid and base - they destroy each other to form a salt (ionic bond) and water.

Cl + Na NaCl + H2O

Acid + base salt + water

Neutralization is A double replacement reactions.

H OH

• Acids and bases destroy each other – neutralization • Neutralization is a double replacement reaction.

• Products of neutralization:Water – H+ of the acid plus OH- of the base.

+ + Acid base H OHK H2OBrH OHKBr

Salt - positive ion (metal) of the base and the negative ion of the acid.

salt water