A Study of the Types of Reactions

 

 

There are four types of chemical reactions:  synthesis, decomposition, single replacement, and double replacement.  These reactions can be observed by noting a physical change in the nature of the reactants.

 

Changes in physical characteristics which give a hint to the chemical changes occurring in a reaction include the formation of a precipitate, the generation of a gas, a change in the color of the solution or the generation or absorption of heat.  Not all chemicals react with one another, but when a reaction does occur, some change in characteristics will be noted.

 

The following lab explores the reaction of ions in solution.  Careful observations should be made in order to separate the reactive pairs from the non-reactive ones.

 

Pre-Lab Questions

 

  1. What is a precipitate?
  2. What is a net ionic equation?
  3. Determine ways in which the occurrence of a reaction can be identified.
  4. What is the formula of a nitrate group?
  5. What group are the alkali metals?  Alkaline earth metals?
  6. How is the presence of a gas in a chemical reaction identified?

 

Materials Needed

 

                        Chemicals                                                    Hardware

 

            Group A – 0.1 M solutions                                    Test Tubes

                        Copper (II) nitrate                                        

                        Nickel (II) nitrate

                        Lead (II) nitrate

                        Cobalt (II) nitrate

                        Nitric acid

                        Silver nitrate

                        Iron (III) nitrate

 

            Group B – 0.1 M solutions

                        Sodium carbonate

                        Sodium sulfate

                        Sodium chloride

                        Sodium thiocyanate

                        Sodium chromate

                        Sodium dichromate

                        Sodium hydroxide

 

 

Directions

 

·         The object of this experiment is to mix each of the reagents in Group A with each of the reagents in Group B. 

 

 

Questions

 

1.         Which combinations resulted in a reaction?  Be specific using names or formulas of combinations.

2.         Which reactions resulted in a precipitate?

3.         Which resulted in the generation of a gas?

4.         What do the compounds in Group A of this laboratory investigation have in common?  Why is this commonality important in the study of reactions?

5.         What substitutions could be made in Group B and still maintain the same “types” of reactions?