Question

In one experiment, a student determined that 2.595 grams of an unknown had a volume of 6.55 mL. If the molar mass of the unknown was 129.32 g/mol, what was the molar volume (in mL) of the unknown?

(A) 129.32 mL/mol
(B) 2.595 mL/mol
(C) 6.55 mL/mol
(D) 7.26 mL/mol

Answer 1

The molar volume of the unknown substance is calculated by dividing its molar mass (129.32 g/mol) by its density. However, the calculated molar volume does not match any of the multiple-choice options provided in the question.

Step-by-step explanation:

To calculate the molar volume of the unknown substance, we need to first determine its density. Density is calculated by dividing the mass by the volume. Given the mass of the substance is 2.595 grams and its volume is 6.55 mL, the density is:

Density = mass / volume = 2.595 g / 6.55 mL = 0.396 g/mL

Now, we know the molar mass of the substance is given as 129.32 g/mol. To find the molar volume, we divide the molar mass by the density:

Molar Volume = molar mass / density = 129.32 g/mol / 0.396 g/mL

This calculation yields a molar volume of approximately 326.6 mL/mol. However, this answer doesn't match any of the options provided (A to D), implying there might be a mistake in the question or the options themselves. According to the options presented, the correct calculation method or choice does not align with the standard approach to determine molar volume.