Final answer:
To find out how many atoms are in 135 g of calcium, calculate the number of moles by dividing the mass by the molar mass of calcium and then multiply by Avogadro's number. This results in approximately 2.03×10²´ atoms of calcium.
Step-by-step explanation:
The question is asking how many atoms are in 135 g of calcium. To find the answer, you first need to calculate the number of moles of calcium in 135 g. Since the atomic mass of calcium (Ca) is approximately 40.078 amu, you can use the formula:
Number of moles = mass (g) / molar mass (g/mol)
So, for 135 g of calcium, you have:
Number of moles of Ca = 135 g / 40.078 g/mol = 3.367 moles of Ca (approximately)
To get the number of atoms, you multiply the number of moles by Avogadro's number (6.02×10²³ atoms/mol):
Number of Ca atoms = 3.367 moles × 6.02×10²³ atoms/mol
This equals approximately 2.03×10²´ atoms of calcium.