How many atoms are in 175 g of calcium?

Question

How many atoms are in 175 g of calcium?

Answer 1

In order to find the number of atoms in a given mass of a substance, you need to first find the molar mass of the substance in question.

In this question, the substance is Calcium. We can find the molar mass on the periodic table which is 40.078g/mol.

We can find the number of moles of this substance by dividing our given mass in grams by our molar mass.

175g / 40.078g/mol = 4.366mol

Then, we need to convert moles to atoms which we do with Avogadro's constant which is 6.022*10^23atoms/mol.

4.366mol * 6.022*10^23atoms/mol = 2.629*10^24 atoms of Ca in 175g of Ca