In a dimensional analysis diagram converting grams of NaCl to moles of NaCl, which conversion factor would best fit in the space labeled 'b' between grams NaCl and moles NaCl?

• A. 1 mol NaCl / 58.44 g NaCl
• B. 58.44 g NaCl / 1 mol NaCl
• C. 6.022 × 10^{23} molecules NaCl / 1 mol NaCl
• D. 1 mol NaCl / 6.022 × 10^{23} molecules NaCl

Answer: (A)

Verified step by step guidance

1. Identify the units you are starting with and the units you want to end with. Here, you start with grams of NaCl and want to convert to moles of NaCl.
2. Recall that the molar mass of NaCl is the key conversion factor between grams and moles. The molar mass of NaCl is 58.44 g/mol, meaning 1 mole of NaCl weighs 58.44 grams.
3. Set up the conversion factor so that grams cancel out and moles remain. Since you start with grams, place grams in the denominator and moles in the numerator: \(\frac{1\ \text{mol NaCl}}{58.44\ \text{g NaCl}}\).
4. Verify that the units cancel correctly: grams in the numerator (from the given quantity) will cancel with grams in the denominator of the conversion factor, leaving moles as the final unit.
5. Note that other options involving Avogadro's number relate moles to molecules, not grams to moles, so they are not appropriate for this step.