When a molar mass is determined from freezing-point depression, it is possible to make each of the following errors (among others). In each case, predict whether the error would cause the reported molar mass to be greater or less than the actual molar mass.

(a) There was dust on the balance, causing the mass of solute to appear greater than it actually was.

(b) The water was measured by volume, assuming a density of 1.00 g · cm^–3, but the water was warmer and therefore less dense than assumed.

(c) The thermometer was not calibrated accurately, and so the temperature of the freezing point was actually 0.5°C higher than recorded. 

(d) The solution was not stirred sufficiently, and so not all the solute dissolved.