Evidence of chemical reactions

Lab Practice 1
“Evidence of chemical reactions”

Introduction:
In a chemical change, which is also called a chemical reaction, the atoms of a substance are rearranged. A chemical changerequires that the new substance have a chemical composition that is different from the composition of the original substance. Some signs of chemical changes are: color change, bubbling and fizzing (a gas isproduced), light or heat production (the release of energy), and the formation of a solid.

Objective:
The main purpose of this practice is to identify several evidences of chemical reactions indifferent products. Do all the evidences appear in each of the reactions?

Procedure:
Add 10 drops of Chloridric Acid to the sample of Zinc.
Add 10 drops of Silver Nitrate to the sample of Copper.Add ten drops of Barium Chloride and ten drops of Sodium Sulfate into a test tube.
Add ten drops of Lead (II) Nitrate and ten drops of Potassium Iodine into a test tube.
Hold a strip of Magnesiumwith priers and turn the burner on.

Results:
Reactant 1 Reactant 2 Product Evidence(s) of chemical change Type of reaction
HCl Zn ZnCl + H Bubbles, heat. Single replacement
AgNO3 Cu CuNO3 +Ag Precipitate, change in color. Single replacement
BaCl2 Na2SO4 BaSO4 + NaCl Change in color. Double replacement
Pb(NO3)2 KI KNO3 + PbI Precipitate, change in color. Double replacement
Mg HeatLight. Exothermic

Discussion:
My teammates and I consider these answers as correct because we have proven them by performing the corresponding chemical reactions. We tried to identify also whatkind of reaction was involved but we think that it is a little bit harder because we don’t have the practice enough to recognize them and we don’t know either the characteristics of each substance so wecould identify them in the reaction only by watching.

Conclusion:
I think that this practice was really important, just as the others, for us to start identifying certain substances just by...