Question

The number of neutrons present in 7 mg of c14 is

Answer 1

Explanation:

C14 has a molecular weight of 14 grams per mole. So that means that 7 milligrams would be 1/2 times 10^-3 moles. A mole is 6.022 x 10^23 atoms, so this means we have 3.011 x 10^-20 atoms of C14.

Now, we all know that carbon has 6 protons. That is what makes it carbon, as opposed to, say, nitrogen or boron. The 14 in C14 means it has 14 protons and neutrons together in the nucleus. So, knowing we have 6 protons, we also know the remaining 8 are neutrons.

So now we have 3.011 x 10^20 atoms x 8 neutrons per atom is 2.4 x 10^21 neutrons in total. That’s a LOT of neutrons! (well they’re really tiny so a lot fit into things but it’s still something to wonder at).