How many atoms are in 157 g of calcium?

Answer 1

Recall the Avogadro constant - 6.022E23 - which is the number of atoms in one mole of a substance.

So to find out how many atoms are in 157 g of calcium, we first need to calculate how many moles 127g of calcium is equal to. To do this we need the molar mass of calcium - 40.08g.

1. 157g Ca/1 x 1 mol Ca/40.08g Ca = 3.92 mol

Now that know how many moles of Ca there are, we can multiply by Avogadro's constant to calculate the number of atoms in 3.92 mol of CA.

1. 3.92 x 6.022E23 = 2.36E24

Therefore, there are 2.36 x 10²⁴ atoms in 157 g of calcium.