Source: Laboratory of Dr. Neal Abrams — SUNY College of Environmental Science and Forestry

Determining the composition of a solution is an important analytical and forensic technique. When solutions are made with water, they are referred to as being aqueous, or containing water. The primary component of a solution is referred to as the solvent, and the dissolved minor component is called the solute. The solute is dissolved in the solvent to make a solution. Water is the most common solvent in everyday life, as well as nearly all biological systems. In chemistry labs, the solvent may be another liquid, like acetone, ether, or an alcohol. The solute can be a liquid or a solid, but this experiment only addressesthe determination of solids.

1. Percent by Mass - Direct

1. Place a small volume of a solution into a clean and oven-dried beaker or crystallization dish.
2. After accurately determining the precise total mass of the solution, heat the beaker or dish on a hotplate or in an oven to drive off the water. Slow evaporation is the best method, as boiling can result in splattering of the solution.
3. Once the solvent has evaporated, cool the remaining solid (solute) and determine the mass.
4. Calculate the mass percent as:
   

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