A student has a sample of isopropanol (C3H7OH) that has a mass of 78.6 g. The molar mass of isopropanol is 60.1 g/mol. How many moles of isopropanol are contained in this sample?
Answer
A
0.765 moles
B
1.31 moles
C
78.6 moles
D
4,720 moles
Explanation
Use moles = mass ÷ molar mass. For this sample, 78.6 g ÷ 60.1 g/mol = 1.31 mol, to three significant figures. Therefore, the sample contains 1.31 moles of isopropanol.
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