Multiple Choice
How many iron atoms are present in a 354 g sample of iron (Fe)?
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2. Atoms & Elements
Calculating Molar Mass
Multiple Choice
What is the molar mass of C2H6O (ethanol)? Report your answer to the nearest integer.
A
60 g/mol
B
46 g/mol
C
34 g/mol
D
40 g/mol
Verified step by step guidance1
Identify the molecular formula of ethanol, which is C2H6O, meaning it contains 2 carbon (C) atoms, 6 hydrogen (H) atoms, and 1 oxygen (O) atom.
Find the atomic masses of each element from the periodic table: carbon (C) is approximately 12 g/mol, hydrogen (H) is approximately 1 g/mol, and oxygen (O) is approximately 16 g/mol.
Calculate the total mass contributed by each element by multiplying the number of atoms by their atomic masses: for carbon, multiply 2 by 12 g/mol; for hydrogen, multiply 6 by 1 g/mol; for oxygen, multiply 1 by 16 g/mol.
Add the masses of all the elements together to get the molar mass of ethanol: \(\text{Molar mass} = (2 \times 12) + (6 \times 1) + (1 \times 16)\) g/mol.
Sum the values from the previous step to find the total molar mass, then round the result to the nearest integer to report the molar mass of ethanol.
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