Copper, H2o and Its Empirical Formula

Introduction/Purpose

Water molecules are known to easily latch onto solid substances considering its polarity; in turn this makes those water molecules “water of hydration”. In this experiment, a hygroscopic compound: chlorine, copper, and water was separated by first heating the compound, whilst calculating the water of hydration and then creating another chemical reaction using the now dried sample. Also by measuring the masses of the separated samples at different intervals, the mols of copper, water, and chlorine were found, thus giving the necessary amount of information in order to find the empirical formula of the compound.

Materials

Crucible with cover

Tongs

Ring stand, ring and clay triangle

Burner

50 mL beaker

Watch glass

Unknown solid copper chloride hydrate

Aluminum Wire

6 M hydrochloric acid, Hcl solution

Distilled water

Glass stirring Rod

Match

Methods

In order to properly continue through the lab, it is necessary to record the mass of each compound, substance, and container periodically. First, record the mass of the crucible with its cover, measure out 1 gram of the compound and place it inside of the crucible. The new mass of the compound inside of the crucible must be recorded also. Next, carefully balance the crucible in the triangle portion connected to the ring stand. Once stable, tilt the lid on the crucible so that the water will be able to escape when heated. Continuing, have another person ignite the gas while another is standing by ready to light the match. Once lit, toggle with the opening of metal on the gas until two explicit blue flames evenly appear. Then, move the flame gently around the bottom of the crucible until the all the water evaporates leaving a brown compound. Now remove the crucible to cool and after remeasure the mass of it. The new mass needs to be subtracted from the previous mass in order to figure out how much hydration of water was present. Transfer the new compound into the beaker provided using water to remove all of the substance completely. Form the aluminum into a circle, place it into the baker and fill it with distilled water until completely submersed. Leave sitting for at least 30 minutes in order for the chemical reaction to occur completely. To speed up the process, add 5-6 drops of the HCL solution to the mixture. Once the wire has been completely covered by the newly formed copper, drain all the water out of the beaker and scrape the copper off the wire and onto the watch glass. Now, turn the hot plate to a medium-low setting, place the watch glass on there and watch until the copper is dry, almost flakey. Finally, measure the mass of the glass and subtract the previous mass of the empty glass in order to get the mass of the copper by itself. Using the data table, figure out the mols to calculate the empirical formula.

Data

Mass of Crucible (g)

37.97 g

Mass of Crucible and Hydrated Sample (g)

38.00 g

Mass of Hydrated Sample (g)

1.03 g

Mass of Crucible and Dehydrated Sample (g)

37.69