To find the number of moles in a given mass of a substance, you can use the formula:
Number of moles = Mass (g) / Molar mass (g/mol)
For calcium (Ca), the molar mass is approximately 40.08 g/mol. Now, plug in the values:
Number of moles = 9.8 g / 40.08 g/mol
Calculating this gives:
Number of moles ≈ 0.244 moles
Therefore, there are approximately 0.244 moles in 9.8 grams of calcium.