Multiple Choice
Which statement best describes the mass percent of water in an apple if the apple has a total mass of 150 g and contains 120 g of water?
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3. Chemical Reactions
Mass Percent
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What is the mass percent of aluminum (Al) in aluminum sulfate, Al_2(SO_4)_3?
A
20.2%
B
34.6%
C
15.8%
D
9.8%
Verified step by step guidance1
Identify the chemical formula of aluminum sulfate, which is \(\mathrm{Al_2(SO_4)_3}\).
Calculate the molar mass of aluminum sulfate by summing the atomic masses of all atoms in the formula: multiply the atomic mass of aluminum (Al) by 2, sulfur (S) by 3, and oxygen (O) by 12 (since there are 4 oxygens per sulfate and 3 sulfate groups).
Calculate the total mass contributed by aluminum atoms alone by multiplying the atomic mass of aluminum by 2.
Use the formula for mass percent: \(\text{Mass percent of Al} = \left( \frac{\text{Mass of Al in the formula}}{\text{Molar mass of } \mathrm{Al_2(SO_4)_3}} \right) \times 100\%\).
Substitute the values calculated in the previous steps into the formula and simplify to find the mass percent of aluminum in aluminum sulfate.
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