Questions: Using mass percent composition to find solution volume A chemistry student needs 70.0 g of 1 -bromobutane for an experiment. She has available 1.5 kg of a 34.8 % w / w solution of 1 -bromobutane in diethyl ether. Calculate the mass of solution the student should use. If there's not enough solution, press the "No solution" button. Round your answer to 3 significant digits. g

Solution Steps

We need to find the mass of a $34.8\% \mathrm{w}/\mathrm{w}$ solution of 1-bromobutane in diethyl ether that contains 70.0 g of 1-bromobutane.

The mass percent composition formula is: \[ \text{Mass percent} = \left( \frac{\text{mass of solute}}{\text{mass of solution}} \right) \times 100\% \] Given:

• Mass percent of 1-bromobutane = 34.8%
• Mass of 1-bromobutane needed = 70.0 g

We need to find the mass of the solution (\(m_{\text{solution}}\)).

Rearrange the mass percent composition formula to solve for the mass of the solution: \[ m_{\text{solution}} = \frac{\text{mass of solute}}{\text{mass percent}} \times 100\% \]

Substitute the given values into the equation: \[ m_{\text{solution}} = \frac{70.0 \, \text{g}}{34.8\%} \times 100\% \]

Convert the percentage to a decimal and calculate: \[ m_{\text{solution}} = \frac{70.0 \, \text{g}}{0.348} \approx 201.1494 \, \text{g} \]

Round the result to 3 significant digits: \[ m_{\text{solution}} \approx 201 \, \text{g} \]

Final Answer