Question

a chemistry student needs 60.0 g of 2-methylpyrazine for an experiment. he has available 250. g of a 26.3% w/w solution of 2-methylpyrazine in water.
calculate the mass of solution the student should use. if theres not enough solution, press the
o solution\ button.
round your answer to 3 significant digits.
□ g

Explanation:

Step1: Find mass of solute in solution

First, calculate how much 2-methylpyrazine is in the available solution. The mass of solute is mass percent times total solution mass.
$\text{Mass of solute} = 0.263 \times 250. \text{ g} = 65.75 \text{ g}$

Step2: Compare to required mass

The student only needs 60.0 g, which is less than 65.75 g, so we can calculate the required solution mass. Rearrange the mass percent formula to solve for total solution mass:
$\text{Mass of solution} = \frac{\text{Required solute mass}}{\text{Mass percent}}$

Step3: Compute final solution mass

Substitute the values into the rearranged formula.
$\text{Mass of solution} = \frac{60.0 \text{ g}}{0.263} \approx 228.137 \text{ g}$

Step4: Round to 3 significant digits

Round the calculated value to 3 significant figures.
$228.137 \text{ g}
ightarrow 228 \text{ g}$

Answer:

228 g