Question

A student failed to clean their equipment resulting in an impurity during this experiment. The impurity is insoluble in water and was on the scoopula and therefore not in the test tube when it was tared. How will this reading affect the molar mass determination?

A) Too low. The impurity will cause the change in temperature to be larger, causing the mol solute to be too large. Since molar mass is g/mol, the molar mass will be calculated too low.

B) No affect. The impurity will cause the change in temperature to be larger, causing the mol solute to be too large. However, the grams of the solute will also be too large. Since molar mass is g/mol, the molar mass will not be affected.

C) Too high. The grams of impurity will be added to the mass of the solute. It will not cause a change in temperature since it is insoluble. Since molar mass is g/mol, the molar mass will be calculated too low.

D) No affect. The solute is insoluble and will not change the freezing point so the mol solute are unaffected. The grams of solute is also unaffected so molar mass will not be affected.