Basic chemistry help for students and teachers

 

Interactive Chemistry Worksheets for Students

 

Periodic table

Naming compounds

Basic formula

Simple compounds

Ionic compounds 1

Ionic compounds 2

Chemical suffixes

Old chemical names

Hydrocarbons - Alkanes

Alkanes, alkenes & alkynes

Alkanols to alkanoic acids

 

Common compounds

Common formula quiz

Acids, bases and salts

Covalent compounds

Printable worksheets
 

 

 

What are acids and bases?

Information

Acids

Alkalis (soluble base)

Taste

Sour

Bitter

Concentrated solutions are

corrosive – dissolve metals

caustic – cause burns

Litmus paper

Turn blue litmus pink

Turn pink litmus  blue

Neutralization

Neutralize bases to produce salt + water

Neutralize acids to produce salt + water

Formation of ions

(charged particles)

Produce hydrogen ions H+ in water

Produce hydroxide ions OH-  in water.

Other reactions

React with active metals to produce hydrogen.

React with fats to produce soap.

Common uses

Car batteries, swimming pools, cleaning mortar off bricks and preserving foods by pickling.

Cleaning products like cloudy ammonia and oven cleaners.

Examples

Sulfuric acid, hydrochloric acid and acetic acid.

Ammonia and sodium hydroxide

 

Acids and bases were first thought as follows. An acid is a substance that tastes sour and a base is a substance that tastes bitter.  eg. citric acid tastes sour. Bi-carb of soda tastes bitter or soapy.

Most acids and bases however, are NOT SAFE to taste. eg. Sulfuric acid used in car batteries and caustic soda or sodium hydroxide which is used in oven cleaners.

A strong base is soluble in water and is called an alkali. Alkali solutions are caustic and can cause severe burns. Alkali solutions dissolve fats and are used as cleaning agents. Examples include cleaning products containing cloudy ammonia and oven cleaners which contain caustic soda or sodium hydroxide.

All alkalis are bases however, not all bases are alkalis. Many bases have a low solubility.

Alkali (strong bases - soluble) Bases (low solubility)
Name Chemical formula Name Chemical formula
 Sodium hydroxide  NaOH  Magnesium hydroxide  Mg(OH)2
 Potassium hydroxide  KOH Calcium hydroxide  Ca(OH)2
 Ammonia  NH3  Aluminum hydroxide  Al(OH)3

 

The oxides of the Group I  elements or alkali metals all dissolve in water to produce alkali solutions.

Eg. Sodium oxide + water → sodium hydroxide

      Na2O + H2O → 2NaOH

 

Strong acids are corrosive in nature and dissolve active metals like magnesium, zinc and iron. examples of strong acids include sulfuric acid, hydrochloric acid and nitric acid.

Name of acid Chemical formula
Hydrochloric acid HCl
Nitric acid HNO3
Nitrous acid HNO2
Acetic acid CH3COOH
Sulfuric acid  H2SO4
Sulfurous acid  H2SO3
 Carbonic acid  H2CO3
 Phosphoric acid  H3PO4

 

Soluble non-metallic oxides dissolve in water to produce acidic solutions.

Eg. Water + carbon dioxide → carbonic acid

      H2O + CO2 →H2CO3

 

What is a chemical indicator?

Chemical indicators are substances that change color in the presence of an acid or base. They can be used to safely determine if a substance is acidic or basic.

Examples of chemical indicators include litmus paper, phenolphthalein, bromothymol blue, methyl red and methyl orange. Litmus is pink in acidic solutions and blue is basic solutions.

 

The Bromothymol Blues Song

A great Chemistry song by Mark Rosengarten