Chapter 10

ACIDS and BASES

PROPERTIES OF ACIDS

All acids contain the element hydrogen in a combined form.

HC2H3O2 acetic acid (vinegar)HCl hydrochloric acidH2SO4 sulphuric acid

All acids have a sour taste. Acids are corrosive (eat away or

destroy a substance.)

Acids react with metals to produce hydrogen gas and a salt.

Zn + 2 HCl ZnCl2 + H2

Acids react with carbonates (CO32-) or

bicarbonates (HCO31-) to produce

carbon dioxide, water and a salt. 2HCl + CaCO3 CO2 + H2O + CaCl2

PROPERTIES OF ACIDS

Acids are good electrolytes. Acids are produced by reacting non-

metallic oxides with water. These non-metallic oxides are called acid anhydrides.

SO3 + H2O H2SO4

PROPERTIES OF ACIDS

Acids change the colour of indicators.Red litmus paper remains redBlue litmus paper turns redPhenolphthalein remains colourlessBromthymol blue turns yellowMethyl orange turns red

PROPERTIES OF ACIDS

PROPERTIES OF BASES

Most bases contain the hydroxide ion (OH-). NaOH sodium hydroxide Ca(OH)2 calcium hydroxide

NH4OH ammonium hydroxide

Some bases contain the bicarbonate ion (HCO3-). NaHCO3 sodium bicarbonate

KHCO3 potassium bicarbonate

All bases have a bitter taste and feel slippery, slimy or soapy

Bases are good electrolytes. Bases are caustic (eat away flesh)

PROPERTIES OF BASES

Bases are prepared by: an active metal reacting with water.

Ca + H2O Ca(OH)2 + H2

A metallic oxide reacting with water. These metallic oxides are called basic anhydrides.

Na2O + H2O 2NaOH

PROPERTIES OF BASES

Bases change the colour of indicators.Red litmus paper turns blueBlue litmus paper remains bluePhenolphthalein turns pinkBromthymol blue remains blueMethyl orange remains orange

PROPERTIES OF BASES

Definitions of Acids and Bases

Arrhenius Theory An acid ionizes in water to increase the

hydrogen ion concentration.A base dissociates in water to increase the

hydroxide ion concentration.A neutralization reaction involves the

reaction of a hydrogen ion with a hydroxide ion to produce water.

Time to Get To Work

Learning Check pg 457# 1- 4, 6