Question

a single atom of calcium, ca, has a mass of 40.08 amu. what is the mass, in grams, of 6.02 x 10²³ atoms of calcium?
? grams

Explanation:

Step1: Recall Avogadro's number meaning

Avogadro's number ($6.02\times10^{23}$) of atoms of an element is equal to 1 mole of that element, and the mass of 1 mole of an element (in grams) is equal to its atomic mass (in amu).

Step2: Calculate the mass

Given the atomic mass of Ca is 40.08 amu, so 1 mole (or $6.02\times10^{23}$ atoms) of Ca has a mass of 40.08 grams. So the mass of $6.02\times10^{23}$ atoms of Ca is 40.08 grams.

Answer:

40.08