mass of solute = 25.0 g
mass of solvent = 40.0 g
percent by mass
[tex]\text{percent by mass} = \dfrac{\text{mass of solute}}{\text{mass of solute + mass of solvent}} \times 100[/tex]
[tex]\text{percent concentration} = \dfrac{\text{25.0 g}}{\text{25.0 g + 40.0 g}} \times 100[/tex]
percent by mass = 38.5%
[tex]\\[/tex]
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