3. Chemical Reactions

Mass Percent

Open Question
Calculate the mass percent composition of lithium in Li₃PO₄.
Multiple Choice
What is the percent by mass of sodium in NaCl? Choose the closest value.
Multiple Choice
What is the percent by mass of carbon in C_{10}H_{14}N_{2}?
Multiple Choice
An oxide of iron has the formula Fe_3O_4. What is the mass percent of iron in Fe_3O_4?
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Multiple Choice
Which element has a mass percent composition of 21.49% in borax (Na2B4O7·10H2O)?
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Multiple Choice
What is the percent by mass of carbon in acetone (C3H6O)?
Open Question
What is the percent by mass of chlorine in NaCl? Use mc002-1.jpg. 35.45% 39.34% 60.66% 70.90%
Multiple Choice
What is the mass percentage of carbon (C) in caffeine, C₈H₁₀N₄O₂? Provide an answer to two decimal places.
Open Question
What is the percent composition of Mg in the compound Mg₃(PO₄)₂?
Open Question
A 500 gram iron ore sample was determined to contain 242 grams of iron. What is the mass percent of iron in the ore?
Multiple Choice
What is the mass percentage of carbon in dimethyl sulfoxide (C2H6SO), rounded to three significant figures?
Multiple Choice
What is the percent by mass of sodium chloride in a 1.40 M NaCl solution with a density of 1.07 g/mL?
Open Question
What is the alcohol content of a 20-oz beer that contains 5% alcohol?
Open Question
A 69.5 g sample of the compound X₃O₄ contains 19.2 g of oxygen atoms. What is the molar mass of element X?
Open Question
What mass of a 4.00% NaOH solution by mass contains 15.0 g of NaOH?