Multiple Choice
A compound has a molar mass of 180 g/mol and the following composition by mass: 40.0% C, 6.7% H, and 53.3% O. What is the molecular formula of the compound?
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2. Atoms & Elements
Calculating Molar Mass
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What is the molar mass of propane (C3H8)?
A
36.05 g/mol
B
58.12 g/mol
C
30.07 g/mol
D
44.10 g/mol
Verified step by step guidance1
Identify the molecular formula of propane, which is C\_3H\_8, meaning it contains 3 carbon atoms and 8 hydrogen atoms.
Find the atomic masses of carbon and hydrogen from the periodic table: approximately 12.01 g/mol for carbon and 1.008 g/mol for hydrogen.
Calculate the total mass contributed by carbon atoms by multiplying the number of carbon atoms by the atomic mass of carbon: \$3 \times 12.01$ g/mol.
Calculate the total mass contributed by hydrogen atoms by multiplying the number of hydrogen atoms by the atomic mass of hydrogen: \$8 \times 1.008$ g/mol.
Add the total masses of carbon and hydrogen together to get the molar mass of propane: \((3 \times 12.01) + (8 \times 1.008)\) g/mol.
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