A sample contains 351 kg of calcium (Ca). How many moles of calcium are present in the sample? (Molar mass of Ca = 40.08 g/mol)

• A. 351 mol
• B. 8,760 mol
• C. 8,760,000 mol
• D. 14,040 mol

Answer: (C)

Verified step by step guidance

1. Identify the given information: mass of calcium (Ca) is 351 kg, and the molar mass of Ca is 40.08 g/mol.
2. Convert the mass of calcium from kilograms to grams because the molar mass is given in grams per mole. Use the conversion: \$1\ \text{kg} = 1000\ \text{g}$, so multiply 351 kg by 1000 to get the mass in grams.
3. Use the formula to calculate moles: \(\text{moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}}\).
4. Substitute the values into the formula: divide the mass in grams by 40.08 g/mol to find the number of moles of calcium.
5. Interpret the result to understand the scale of moles present in the sample, ensuring the units are consistent and the answer makes sense given the large mass.