Chemistry Report

Purpose

The purpose of this lab was to determine the identity of two unknown substances, as well as determine how many moles of water were present in every mole of substance.

Procedure

First, the unknown substances were obtained. Using each of the aqueous solutions provided (hydrogen chloride, sulfuric acid, ammonia, sodium hydroxide, barium chloride, magnesium sulfate, sodium carbonate, sodium sulfate, sodium acetate) and following the chart on page 65 of the lab book, mixtures were made in order to determine the unknowns. For instance, barium chloride was mixed with all of the aqueous solutions, and the results were logged on the chart. Following that, magnesium sulfate was mixed with all of the aqueous solutions, then sodium carbonate, then sodium sulfate, then sodium carbonate. All results were logged. After discovering what reactions took place with the knowns, all of the aqueous solutions were mixed with the first unknown and recorded. The same procedure occurred with the second unknown. The results of the unknowns were compared to the reactions of the given solutions. Using this information, it was determined that the first unknown consisted of barium chloride, while the second unknown consisted of sodium carbonate.

The first step in determining the molar ration of water to substance was to wash and dry the crucible and lid to be used. The empty crucible was weighed, and the mass was recorded. Following that, a small amount of the barium chloride was added to the crucible, and the mass was obtained and recorded. The crucible was then heated for four minutes to eliminate all water out of the sample of barium chloride. After allowing the crucible to cool, the mass was taken again and recorded. By subtracting the heated amount from the original amount, the weight of the water was found. To find the number of moles of water per moles of barium chloride, the weight of the water was divided by the molecular weight of water and recorded. Similarly, the

weight of the barium chloride given was divided by the molecular weight of barium chloride. By dividing the weight of the water by the weight of the barium chloride, a 3:1 ratio was obtained, meaning that there are approximately three moles of water present in every mole of barium chloride. The same procedure was followed for the sodium carbonate, resulting in a 1:1 ratio, meaning that for every mole of water, there is a mole of sodium carbonate.