## creekrat48 3 years ago from this graph How much nitrogen-14 will be produced from a 200-g sample of carbon-14 after 17,190 years?

1. creekrat48

2. zbay

how many half lifes is that?

3. creekrat48

I am still reading these half lifes in book so confused

4. zbay

3 half lifes meaning there will be an 8th of the atoms left, can you go from mass to atoms?

5. creekrat48

I just got that as you did

6. zbay

No i would calculate the atoms total and then divide them by 3/4 and those would be the ones that are N

7. zbay

now ^

8. creekrat48

I'm sorry I just don't understand with the 200 gram sample

9. zbay

do you know how to go from mass-->moles-->atoms?

10. creekrat48

i have done it before but would have to go back into book to reread again

11. zbay

$200g(\frac{1 mole c}{12.01g c})\frac{6.022x10^23 c atom}{1 mole c})$ that will get you atoms,

12. creekrat48

oh my

13. zbay

Does that look like anything you have ever done?

14. creekrat48

yes

15. creekrat48

not that complex

16. zbay

1.00x10^25 is the total (I think i'm using a jankie calculator) now just multiply that number by .875 and that will be the number of nitrogen

17. creekrat48

zbay thank you I guess some people just don't understand that it just doesn't click for me. Another guy was very mean like I am some dumbass.

18. zbay

No chemistry is a ball buster, it takes a lot of practice and everything builds on previous knowledge. If you keep pluging away at it i'm sure you will get a handle on this subject. Good luck and keep asking questions!

19. creekrat48

in 3 half-lifes, 200g carbon-14 will decay to 100-50-25g, so taking that carbon-14 decays to nitrogen-14, 175 g is produced or using the half-life formula, amount of nitrogen-14 produced = 200 - 200*0.5^(17190/5730) = 175 g

20. zbay

Thats a much easier way to do it, It can be calculated the way i explained it sorry if i added to the confusion