A) A student performed the freezing point depression experiment according to directions but mistakenly recorded the mass of lauric acid as 8.300 g instead of 8.003 g. The calculated molar mass of the unknown acid will be ___________ than the true value, because the mass of lauric acid appears in the denominator of the unknown acid's molecular weight determination

A. less
B. greater

(B) therefore, if it was mistakenly recorded too high, it would ___________ the calculated moles of the solute.

A. increase
B. decrease

lol webwork.

the unknown should be less then its true value and the calculated moles would be increased i believe

yup he's right.

To determine the effect of mistakenly recording the mass of lauric acid on the calculated molar mass of the unknown acid, we need to understand the relationship between freezing point depression and mole concentration.

The formula for freezing point depression is:
ΔT = Kf * m
where ΔT refers to the freezing point depression, Kf is the freezing point depression constant, and m represents the molal concentration of the solute.

The molal concentration (m) can be calculated using the following equation:
m = moles solute / mass solvent (in kg)

To find the molar mass of the unknown acid, we rearrange this equation to isolate moles:
moles solute = m * mass solvent (in kg)

In this case, the unknown acid is the solute, and lauric acid is the solvent. The mass of lauric acid is mistakenly recorded as 8.300 g instead of the true value of 8.003 g.

Since the mass of lauric acid appears in the denominator of the unknown acid's molecular weight determination, an increase in its mass (as mistakenly recorded) will result in a decrease in the calculated moles of the solute (the unknown acid).

Therefore, the answer to the first question is (B) greater.

Now let's consider the effect of the mistakenly recorded mass of lauric acid on the calculated moles of the solute. As we established previously, an increase in the mass of lauric acid will lead to a decrease in the calculated moles of the solute.

Therefore, the answer to the second question is (B) decrease.