SAMPLE PROBLEM 13.4
Expressing concentration in parts by mass, parts by volume, and mole fraction
PLAN:
PROBLEM:
(a) Find the concentration of calcium (in ppm) in a 3.50 g pill that contains 40.5 mg of Ca.
(b) The label on a 0.750 liter bottle of Italian chianti indicates “11.5% alcohol by volume”. How many liters of alcohol does the wine contain?
(c) A sample of rubbing alcohol contains 142 g of isopropyl alcohol (C3H7OH) and 58.0 g of water. What are the mole fractions of alcohol and water?
(a) Convert mg to g of Ca, find the ratio of g Ca to g pill, and multiply by 106.
(b) Knowing the % alcohol and the total volume, the volume of alcohol can be calculated.
(c) Convert g of solute and solvent to moles, and find the ratios of each part to the total.
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