How many moles are present in 15.0 g of AsH_3 (arsine)? (Molar mass of AsH_3 = 77.95 g/mol)

• A. 0.192 mol
• B. 0.513 mol
• C. 5.20 mol
• D. 1.95 mol

Answer: (A)

Verified step by step guidance

1. Identify the given information: mass of AsH_3 = 15.0 g, molar mass of AsH_3 = 77.95 g/mol.
2. Recall the formula to calculate moles from mass and molar mass: \(\text{moles} = \frac{\text{mass}}{\text{molar mass}}\).
3. Substitute the given values into the formula: \(\text{moles} = \frac{15.0\ \text{g}}{77.95\ \text{g/mol}}\).
4. Perform the division to find the number of moles (do not calculate the final value here, just set up the expression).
5. Interpret the result as the amount of substance in moles present in the 15.0 g sample of AsH_3.