# Help with carbon dating question please

1. Jul 21, 2011

### cd95

desperately need help with the question below. me and my dad have been working on it for hours but keep getting the answer to be 5.97x10^-23???!!!! totally off what it should be.

Q. There are about 1.3x10^-12 carbon-14 atoms for each atom of carbon-12 in living materials, and the half-life of carbon-14 is 5730 years. Show that the number of disintegrations occuring in 1 mole of carbon from a living organism is 2.3 per second.

Thanks

Charley

2. Jul 21, 2011

### ehild

ehild

3. Jul 21, 2011

### cd95

this is what we worked out.....

(1.3x10^-12) x 12 = 1.56x10^-11 gm C14/gm C

then using the equation Kb=ln2/half-life...

Kb=ln2/(1.80x10^11) seconds = 3.85x10^-12 disintegrations per second

Then....
(3.85x10^-12) x (1.56x10^-11) = 5.97x10^-23

what have we missed????

4. Jul 21, 2011

### SteamKing

Staff Emeritus
How many atoms are in one mole of a substance? Remember, it is the number of disintegrations of individual atoms that you are looking for.