How many moles of C_3H_8 are present in 67.8 grams of C_3H_8?

• A. 3.09 moles
• B. 2.50 moles
• C. 0.80 moles
• D. 1.54 moles

Answer: (D)

Verified step by step guidance

1. Identify the given information: the mass of propane (C_3H_8) is 67.8 grams.
2. Calculate the molar mass of propane (C_3H_8) by summing the atomic masses of its atoms: 3 carbon atoms and 8 hydrogen atoms. Use the atomic masses approximately as C = 12.01 g/mol and H = 1.008 g/mol.
3. Write the formula for molar mass calculation: \(\text{Molar mass of } C_3H_8 = (3 \times 12.01) + (8 \times 1.008)\) g/mol.
4. Use the formula to find the number of moles: \(\text{moles} = \frac{\text{mass}}{\text{molar mass}} = \frac{67.8 \text{ g}}{\text{molar mass of } C_3H_8}\).
5. Perform the division to find the number of moles of propane present in 67.8 grams.