How many grams of glucose are required to prepare 400 mL of a 2.0% (m/v) glucose solution?

• A. 8.0 g
• B. 2.0 g
• C. 4.0 g
• D. 20.0 g

Answer: (A)

Verified step by step guidance

1. Understand the meaning of % (m/v) concentration: it represents grams of solute per 100 mL of solution. So, a 2.0% (m/v) glucose solution means 2.0 grams of glucose per 100 mL of solution.
2. Set up a proportion to find the grams of glucose needed for 400 mL. Use the formula: \(\text{grams of solute} = \left( \frac{\text{% (m/v)}}{100 \text{ mL}} \right) \times \text{volume of solution in mL}\).
3. Substitute the known values into the formula: \(\text{grams of glucose} = \left( \frac{2.0}{100} \right) \times 400\) mL.
4. Calculate the multiplication to find the grams of glucose required (do not compute the final number here, just set up the expression).
5. Interpret the result as the mass of glucose needed to prepare 400 mL of a 2.0% (m/v) glucose solution.