Question

Convert molecules of vitamin D (molar mass 384.7 g/mol) to grams of vitamin D. Select the correct units and conversion factors for each step in the following unit roadmap.

A) Molecules → moles → grams
B) Molecules → grams
C) Molecules → moles → milligrams
D) Molecules → milligrams → grams

Answer 1

To convert molecules of vitamin D to grams, the correct pathway is A) Molecules → moles → grams. First, use Avogadro's number to convert molecules to moles, then multiply the number of moles by the molar mass of vitamin D to obtain the mass in grams.

Step-by-step explanation:

To convert molecules of vitamin D to grams, you need to follow a two-step process. The correct unit roadmap would be A) Molecules → moles → grams. This is because you first need to convert the number of molecules to moles using Avogadro's number (6.022 × 10²³ molecules/mole), and then convert moles to grams using the molar mass of vitamin D.

For example, suppose you have 1 × 10²⁴ molecules of vitamin D. First, convert molecules to moles:

1. 1 × 10²⁴ molecules × (1 mole / 6.022 × 10²³ molecules) = approximately 1.66 moles

Then, convert moles to grams:

1. 1.66 moles × 384.7 g/mole = approximately 638.6 grams

This two-step process is necessary because there is no direct conversion between molecules and grams.