chemistry
posted by drew on .
Nitrogen13 has a halflife of 10 minutes. Given a starting mass of 2.00 g of nitrogen13, how many grams will remain at the end of 30 minutes?

k = 0.693/t_{1/2}
ln(No/N) = kt
No = 2.00
N = unknown
k from above
t = 30 min
Solve for N.
You can also use this.
30 min is obviously 3 half lives; therefore, 2^{3} = 8 and 2.00 x (1/8) = ?