Question

You have a pure (24-karat) gold ring with mass 10.8 g. gold has an atomic mass of 197 g/mol and an atomic number of 79. part a how many protons are in the ring

Answer 1

The atomic number of an element is the number of protons found in one atom of the element. In order to determine the total number of protons, we must find the number of atoms present in the gold. We do this by first calculating the moles:


moles = mass / molecular mass
moles = 10.8 / 197
moles = 0.055

Next, we know that one mole of substance contains 6.02 x 10²³ atoms. So the atoms are:

0.055 * 6.02 x 10²³

There are 3.31 x 10²² atoms

Each atom contains 79 protons. The total protons are:

79 * 3.31 x 10²²

There are a total of 2.61 x 10²⁴ protons