Tips for the Teacher

Language of Chemistry

• chemical reaction process by which one or more substances change into new substances.
  
• compound substance composed of two or more elements.
  
• decomposition reaction reaction that results in two or more substances being formed from a single substance.
  
• double replacement reaction reaction in which the positive ions of two compounds are exchanged. "Displacement" is a synonym for "replacement."
  
• element substance that cannot be decomposed into a simpler substance.
  
• mixture two or more substances that are not chemically combined and does not have a fixed set of properties.
  
• precipitate solid formed in a chemical reaction involving solutions.
  
• single replacement reaction reaction in which one element replaces another.
  
• solution homogeneous mixture.
  
• substance sample of matter that has a uniform set of properties and a definite composition. Examples of substances are elements and compounds.
  
• synthesis reaction two or more substances form a single substance in a reaction. Synonyms are "composition" and "combination."

Pattern Recognition

Teaching students to classify reactions is an exercise in pattern recognition.

Synthesis (combination; composition)

Element + Element---> Compound

1. Iron + Sulfur ---> Iron(II) sulfide
   
2. Mercury + Oxygen---> Mercury(II) oxide
   
3. Phosphorus + Oxygen ---> Diphosphorus pentoxide
   
4. Potassium + Chlorine ---> Potassium chloride
   

1. Magnesium oxide + Carbon dioxide ---> Magnesium carbonate
   
2. Sulfur dioxide + Water ---> Sulfurous acid

Decomposition

Compound ---> Two or more simpler substances

1. Water ---> Hydrogen + Oxygen
   
2. Calcium carbonate ---> Calcium oxide + Carbon dioxide
   
3. Sodium nitrate ---> Sodium nitrite + Oxygen
   
4. Copper(II) sulfate pentahydrate --->Copper(II) sulfate + Water

Element + Compound --->Element + Compound

1. Iron(III) oxide + Carbon ---> Iron + Carbon monoxide
   
2. Aluminum + Sulfuric acid ---> Aluminum sulfate + Hydrogen
   
3. Copper(II) sulfate + Iron ---> Copper + Iron(II) sulfate
   
4. Sodium + Water---> Sodium hydroxide + Hydrogen

Double replacement

Two compounds --->Two new compounds

1. Sodium carbonate + Calcium hydroxide ---> Sodium hydroxide + Calcium carbonate
   
2. Iron(II) sulfide + Hydrochloric acid ---> Hydrogen sulfide + Iron(II) chloride
   
3. Magnesium hydroxide + Sulfuric acid---> Water + Magnesium sulfate
   
4. Copper(II) nitrate + Sodium hydroxide ---> Copper(II) hydroxide + Sodium nitrate

	TABLE OF CONTENTS	TOPIC OVERVIEW	CONCEPT/SKILLS DEVELOPMENT	LINKS/CONNECTIONS	APPENDEX