Question

For each reaction write a balanced chemical equation and then below the chemical formula of each reactant and product write a brief description of the substance (color and physical state). Also, indicate whether the reaction is exothermic, endothermic, or cannot tell.

1. Combination Reaction

Equation:

Exothermic                  Endothermic                Cannot tell

Evidence of Chemical Change:

2. Reversible Decomposition--Combination Reactions

1. Dehydration of Blue Vitrol (Copper(II) Sulfate Pentahydrate)

Equation: CuSO₄·5H₂O ® CuSO₄ + 5H₂O

Exothermic                 Endothermic                Cannot tell

Evidence of Chemical Change:

2. Rehydration of Anhydrous Copper(II) Sulfate:

Equation: CuSO₄·5H₂O ® CuSO₄ + 5H₂O

Exothermic                 Endothermic                Cannot tell

Evidence of Chemical Change:

3. Single Replacement Reaction

Equation: Cu + 2AgNO₃ ® 2Ag + Cu(NO₃)₂

Exothermic                 Endothermic                Cannot tell

Evidence of Chemical Change:

4. Double Displacement Reaction--Milk from water:

           

Equation: CaCl₂ + Na₂CO₃ ® CaCO₃ + 2NaC1

Exothermic                 Endothermic                Cannot tell

Evidence of Chemical Change:

5. Mixed Type Reactions: The Alka-seltzer effect:

Equation: CaCO₃+ 2HCl ® CaCl₂ +H₂O + CO₂

Exothermic                 Endothermic                Cannot tell

Evidence of Chemical Change:

6. Three Penny Experiment

Please classify each of the following word equations as a chemical or physical change. Give evidence that supports your classification. (Hint, are all silver colored metals silver, or gold colored metals gold?)

red penny + zinc + zinc chloride solution ® silver penny + zinc + zinc chloride solution

Exothermic                 Endothermic                Cannot tell

Chemical or physical transformation?

Evidence of Chemical Change:

silver penny -®   gold penny

Exothermic                 Endothermic                Cannot tell

Chemical or physical transformation?

Evidence of Chemical Change:

Answer 1