Multiple Choice
What is the molar mass of aspirin (C9H8O4)?
2. Atoms & Elements
Calculating Molar Mass
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What is the mass, in grams, of 1.66 × 10²³ molecules of aspirin, C₉H₈O₄?
A
15.0 grams
B
5.0 grams
C
30.0 grams
D
10.0 grams
Verified step by step guidance1
First, understand that the problem requires converting the number of molecules to mass in grams. To do this, we need to use Avogadro's number, which is approximately 6.022 × 10²³ molecules/mol.
Calculate the number of moles of aspirin molecules by dividing the given number of molecules (1.66 × 10²³) by Avogadro's number (6.022 × 10²³ molecules/mol). This will give you the moles of aspirin.
Next, determine the molar mass of aspirin (C₉H₈O₄). Calculate this by adding the atomic masses of all the atoms in the formula: 9 carbon atoms, 8 hydrogen atoms, and 4 oxygen atoms. Use the periodic table to find the atomic masses: Carbon (C) is approximately 12.01 g/mol, Hydrogen (H) is approximately 1.01 g/mol, and Oxygen (O) is approximately 16.00 g/mol.
Multiply the number of moles of aspirin by the molar mass of aspirin to find the mass in grams. This step converts moles to grams using the molar mass as a conversion factor.
Finally, compare the calculated mass to the given options (15.0 grams, 5.0 grams, 30.0 grams, 10.0 grams) to identify the correct answer.
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