Recall equations for a) molality, b) mole fraction, c) percent by mass and d) ppm

$\overline{){\mathbf{Molality}}{\mathbf{\left(}}{\mathbf{m}}{\mathbf{\right)}}{\mathbf{=}}\frac{\mathbf{moles}\mathbf{}\mathbf{solute}}{\mathbf{kg}\mathbf{}\mathbf{solvent}}}$

$\overline{){\mathbf{mole}}{\mathbf{}}{\mathbf{fraction}}{\mathbf{}}{\mathbf{\left(}}{\mathbf{X}}{\mathbf{\right)}}{\mathbf{=}}\frac{\mathbf{mole}\mathbf{}\mathbf{of}\mathbf{}\mathbf{solute}}{\mathbf{mole}\mathbf{}\mathbf{of}\mathbf{}\mathbf{solution}}}$

$\overline{){\mathbf{m}}{\mathbf{a}}{\mathbf{s}}{\mathbf{s}}{\mathbf{}}{\mathbf{p}}{\mathbf{e}}{\mathbf{r}}{\mathbf{c}}{\mathbf{e}}{\mathbf{n}}{\mathbf{t}}{\mathbf{}}{\mathbf{=}}{\mathbf{}}\frac{\mathbf{m}\mathbf{a}\mathbf{s}\mathbf{s}\mathbf{}\mathbf{c}\mathbf{o}\mathbf{m}\mathbf{p}\mathbf{o}\mathbf{n}\mathbf{e}\mathbf{n}\mathbf{t}}{\mathbf{t}\mathbf{o}\mathbf{t}\mathbf{a}\mathbf{l}\mathbf{}\mathbf{m}\mathbf{a}\mathbf{s}\mathbf{s}}{\mathbf{\times}}{\mathbf{100}}}$

$\overline{){\mathbf{ppm}}{\mathbf{=}}\frac{\mathbf{mass}\mathbf{}\mathbf{of}\mathbf{}\mathbf{solute}}{\mathbf{mass}\mathbf{}\mathbf{of}\mathbf{}\mathbf{solution}}{\mathbf{\times}}{{\mathbf{10}}}^{{\mathbf{6}}}}$

**solute → NaCl**

**solvent → H _{2}O**

A 2.950×10^{−2}*M* solution of NaCl in water is at 20.0°C. The sample was created by dissolving a sample of NaCl in water and then bringing the volume up to 1.000 L. It was determined that the volume of water needed to do this was 999.2 mL . The density of water at 20.0°C is 0.9982 g/mL.

Part A

Calculate the molality of the salt solution. Express your answer to four significant figures and include the appropriate units.

Part B

Calculate the mole fraction of salt in this solution. Express the mole fraction to four significant figures.

Part C

Calculate the concentration of the salt solution in percent by mass. Express your answer to four significant figures and include the appropriate units.

Part D

Calculate the concentration of the salt solution in parts per million. Express your answer as an integer to four significant figures and include the appropriate units.

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