Dissolved Impurities Lab Report

1596 Words 7 Pages
The purpose of this lab is to understand the effect that dissolved impurities will have on the freezing point of a mixture and what additive will affect the the freezing point the most. The freezing point of a liquid is, the point of a substance when the temperature of the solid and the liquid is equal. When water freezes the water molecules become organized and come closer together forming crystal particles of ice.When a solute (like salt) and a solvent (like water) mix together the salt becomes an impurity and makes it so the solution can’t crystallize. This means that the solution remains liquid even when the temperature is lower.
Freezing point depression is when a solution has a lower freezing point than its solvent. This
…show more content…
Ⅵ. Data
See attached data tables.
Ⅶ. Analysis
1.None of the additives were are able to increase the freezing point of the ice water mixture, however the additives were able to lower the freezing point in which the ice melts.
2.An impurity has the effect of lowering the freezing point of a solvent by changing the structure of the solvent. Making it so when the impurity is added the solvent will not be able to crystalize and remains liquid.
3.NaCl was the additive that lowered the freezing point the most in the experiment.
4.C12H22O11 was the additive that lowered the freezing point the least in the experiment.
5.C12H22O11 has the smallest freezing point per moles and AlCl3*6H20 has the greatest freezing point per mole. This is not expected because the additive with the least amount of moles should also have the lowest freezing point. The additive with the greatest amount of moles should also have the highest freezing point.
6.The freezing point depression of a substance should increase as the ions increase. The data recorded shows that freezing point depression increases as particles
…show more content…
The percent error for NaCl is 3.08% error. The additive C12H22O11 had a change in temperature of 1.8*C and the theoretical change in temperature was .616*C. The percent error for this additive is 2.02% error. The additive CaCl2*2H2O had a change in temperature of 5.5*C and a theoretical change in temperature of 3.45*C. The percent error for this additive is 4.6% error. The additive AlCl3*6H2O had a change in temperature of 8.5*C and a theoretical change in temperature of 1.03*C. The percent error for this additive was 8.1% error. My hypothesis was,If the freezing point depends on the number of ions in a substance, then the chemical aluminum chloride will have the greatest impact on the freezing point because it has the maximum amount of ions. My hypothesis was not supported because, NaCl is the additive that had the greatest impact on the freezing point because the concentration of the solution has less water molecules than the water

Related Documents