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? asked in Science & MathematicsChemistry · 1 decade ago

Mass percent in chemistry question?

A 0.498 M solution of lactose, C12H22O11, in water has a density of 1.0432 g/mL at 20 degrees Celsius. What is the mass percent of lactose in this solution? I need to know how to set up and then get the answer to this problem. Thank you.

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  • 1 decade ago
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    0.498 M lactose = 0.498 moles lactose / 1 L solution (342.30 g / 1 mol lactose) = 170.5 g lactose / 1 L (1 mL / 1.0432 g) = 163.4 mL lactose / 1 L solution = 163.4 mL lactose / 1000 mL solution = 0.1634 * 100% = 16.3% by mass

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