Which conversion factor is needed to convert 0.5 mg of a substance to mL, assuming the density of the substance is 1.0 g/mL?

• A. 1 mL / 1 mg
• B. 1 g / 1 mL
• C. 1 mL / 1 g
• D. 1 mg / 1 mL

Answer: (C)

Verified step by step guidance

1. Identify the given information: the mass of the substance is 0.5 mg, and the density is 1.0 g/mL.
2. Recall the definition of density: density (\rho) is mass (m) divided by volume (V), expressed as \(\rho = \frac{m}{V}\).
3. Rearrange the density formula to solve for volume: \(V = \frac{m}{\rho}\).
4. Convert the mass from milligrams (mg) to grams (g) because the density is given in g/mL. Use the conversion factor \$1\ \text{g} = 1000\ \text{mg}$.
5. Use the conversion factor derived from the density to convert grams to milliliters: since density is \$1.0\ \text{g/mL}\(, the conversion factor is \)1\ \text{mL} / 1\ \text{g}$.