Which of the following preparations would give a glucose solution with a concentration of 0.5 M? Select the correct option.

• A. Dissolving 9.0 g of glucose (C6H12O6) in enough water to make 500 mL of solution
• B. Dissolving 18.0 g of glucose (C6H12O6) in enough water to make 200 mL of solution
• C. Dissolving 18.0 g of glucose (C6H12O6) in enough water to make 1 L of solution
• D. Dissolving 9.0 g of glucose (C6H12O6) in enough water to make 100 mL of solution

Answer: (B)

Verified step by step guidance

1. Calculate the molar mass of glucose (C6H12O6) by summing the atomic masses of all atoms: 6 carbons, 12 hydrogens, and 6 oxygens. Use the atomic masses approximately as C = 12 g/mol, H = 1 g/mol, and O = 16 g/mol. The molar mass formula is: \(\text{Molar mass} = 6 \times 12 + 12 \times 1 + 6 \times 16\).
2. Convert the given mass of glucose in each preparation to moles using the formula: \(\text{moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}}\).
3. Convert the volume of the solution from milliliters to liters for each preparation, since molarity is expressed in moles per liter. Use the conversion: \$1\, \text{L} = 1000\, \text{mL}$.
4. Calculate the molarity of each solution using the formula: \(\text{Molarity (M)} = \frac{\text{moles of solute}}{\text{volume of solution in liters}}\).
5. Compare the calculated molarity values for each preparation to the target concentration of 0.5 M to determine which preparation matches this concentration.