ACIDS, BASES, & SALTS

Chapter 17

ACIDSACIDSACID:–An acid is a substance that produces

Hydrogen ions (H+) in a solution.Properties of ACIDS

They are electrolytes (conduct electricity)

They are CorrosiveThey Taste Sour• IMPORTANT – Never use taste to test for an acid*

BASESBASESBases:–A base is a substance that produces

hydroxide ions (OH-) in a solution.Properties of Bases:

–They are electrolytes–They are corrosive (caustic) –They feel slippery–They have a bitter taste

• IMPORTANT – taste should never be used to test for a base*

Strength of Acids & BasesStrength of Acids & BasesThe STRENGTH of an Acid or Base

depends on how completely a compound is broken apartbroken apart to form ions when dissolved in water

The CONCENTRATION of an Acid or Base refers to the amountamount of an Acid or Base in a solution. *

Ions are atoms that have either a positive or negative charge.

pH measures the concentration of hydronium ions (H3O+)in a solution

What is a Hydronium ion?Hydronium ions (H3O+) form when

Hydrogen ions (H+) bond with water*

IonsIons

H+ + H2O H3O+

pHpHpH’s of less than 7 are -

1 2 3 4 5 6 7 8 9 10 11 12 13 14

Neutral

NeutralNeutral

ACIDIC

Acidic

pH’s of greater than 7 are -

BASIC

Basic

pH of exactly 7 is -

Finding the pHFinding the pHTo determine the pH of something,

Use:pH paper – has a plant extract

that changes color at different pH levels.

pH meter – detects how easily electricity can flow through the solution. *

SaltsSaltsA Salt is a compound formed when

negative ions from an acid bond with the positive ions of a base

Salts form through the process of Neutralization.

When Acids and Bases are added together (or Neutralized) their ions form: Salt and Water*

What kind of Change is taking place, – Physical or Chemical?*

Neutralization of Hydrochloric Acid and Sodium Hydroxide

Example:Example:

H2OHCl- + NaOH+ H3O+ + Cl- + Na+ + OH-

H3O+ + OH- 2H2O

Na+ + Cl- NaClSalt forms:

Water forms: