Preparing Crystal Solution Lab

The objective of this experiment is to prepare, grow, and observe crystals of a molecular solid, sucrose (table sugar). A solution is a homogeneous mixture composed of one or more substances, known as solutes, dissolved in another substance, known as a solvent. An example of solutes in this investigation is sugar. Two Major factors affect the solubility of a solid in solution. The solubility of solids decreases as temperature and volume decreases. As volume decreases, less solvent is available to actively dissolve solutes floating around. As the solutions cool and solvent water evaporates from them, the sucrose becomes less and less soluble. Solid Sucrose will then precipitate onto the yarn as the solution continues cooling and evaporating.

In the beginning of this experiment, three samples were created differing in amount of solvent, volume of containers (cups), and types of fiber strings. The solution in each sample is from the same prepared solution of dissolved sugar in hot water. Sample A is the standard solution holding three-fourths of the container full of solvent, a regular piece of yarn string tied to a pencil emersed in the solution, and is contained in styraphoam cup. Sample B is a non-standard solution which is contained in a styraphoam cup but containing different type of string emersed in the solution and also contains less solvent than the standard solution. Sample C is another non-standard solution which is contained in a "paper" cup of larger volume and a regular yarn emersed in the solution. By critically observing the three sample solutions over the period of time from when they were first created, the growth of the crystal and their results differ. It seems that the amount of time for the the solid sucrose to precipitate onto the yarn as its solubility decreases due to the evaporation of the solvent (water) increases as the volume of solution in a sample increases. Therefore Sample C, the solution with more volume, had slower growth than the other samples and failed to produce crystals