question about chem

Question

A 0.9182 g sample of CaBr₂ is dissolved in enough water to give 500.0 mL of solution. A 15.00 mL aliquot of the resulting solution is transferred to a volumetric flask and is diluted to 100.0 mL. Which of the following statements is FALSE?

Select one:

a.

The number of moles of CaBr₂ in the 15.00 mL aliquot and the 100.0 mL solution are equal.

b.

The concentration of the CaBr₂ in the 15.00 mL aliquot and in the 500.0 mL solution are equal.

c.

The concentration of CaBr₂ in the 500.0 mL solution is greater than that in the 15.00 mL aliquot.

d.

The number of moles of CaBr₂ in the 500.0 mL solution is greater than that in the 100.0 mL solution.

Answer 1

(A) is True. Moles are simply a measurement of the number of molecules. There are X number of CaBr₂ molecules in our 15mL aliquot. Adding more solvent doesn't change the number of molecules, just the concentration of them.

(B) is True. The aliquot is taken directly from the sample. Nothing has changed in terms of its concentration because the ratio of molecules to the volume of liquid is constant.

(C) is False. See answer to (B). This answer contradicts the one provided in (B).

(D) is True.