AlinaDeisy.

=Lab#16: Determining the Identity of an unknown hydrate using percent composition water.=

Before anything was done, safety goggles were applied to group members for safety and prevention against accidents. To find the identity of Hydrate 1, a cool crucible was placed on the balance to determine its mass. Two teaspoons of Hydrate 1 were poured inside the crucible to be observed and afterwards were placed on the balance to be weighed. The mass of the crucible with Hydrate 1, was subtracted from the mass of the cool crucible, to find the mass of the hydrate alone without any other substance. A clay triangle was put on top of the iron ring, which was attached to the ring stand. The crucible with the hydrate was carefully placed in the clay triangle using a crucible tong for safety and the burner was 1.5 inches away from the bottom of the crucible. The gas was turned on at a 90 degree angle and was left on for 5 minutes while being observed. After 5 minutes, the sample had turned lighter from its original color and was assumed to have lost water because of the process of evaporation, making it an anhydrate. An anhydrate is a compound that has lost water, dehydrated. Using the crucible tong, the crucible was brought over to the balance to be weighed. The cool crucible with the anhydrate was weighed and subtracted from the cool crucible to get the mass of the anhydrate. To find how much water was lost, the mass of the unknown hydrate was subtracted from the mass of the unknown anhydrate. To find the percent mass of water in the hydrate, the formula is mass of water lost divided by mass of hydrate multiplied by 100. In this case, it was .4g/1.2g x 100 resulting in an answer of 33.3%. The hydrate that was closest to this number is Copper (II) Sulfate pentahydrate whose average calculated percent mass of water is 36%. To find the identity of the Hydrate 3, a cool crucible was placed on the balance to determine its mass. Then a teaspoon of Hydrate 3, a pink/white powdery substance, was placed in a cool crucible, and then placed on a balance to determine the mass. This method was repeated for hydrate 3 to determine its identity as well.