Driving Question: What is the water content of a hydrated salt?
The purpose of this lab was to determine the percentage of water in a hydrate. A crucible was used to heat the hydrated salt, turn it into an anhydrous salt and find the mass of water of hydration. When a hydrated salt turns into an anhydrous salt, the color changes from blue to white. This helps to see whether or not the crystals have completely dehydrated or not. The average molar ratio between the salt and water is a 1:5 ratio.
Hydrated salts are naturally occurring, or manmade salts that contain water molecules bound with the crystal structure of the solid. When separating the water from the crystal structure by heat, the salts become anhydrous salts. This can be expressed in the equation:
By heating the salt, the water evaporated from sample and turned the salt white. When we measured the salt before and after the heating, we found the difference to be the amount of water in the hydrate. To find the percentage mass of water in the hydrated salt we used the equation:
In the experiment we did only one trial on the hydrated copper sulfate to find the water content.