Question

How much nitrogen-13 would be left after 40 minutes if the sample started at 4g

Answer 1

Answer:

0.248 g

Explanation:

We are given;

• Time as 40 minutes
• Original amount of N-13

We are required to calculate the amount left after decay.

• We need to know the half life of N-13 first;
• Half life of N-13 is 9 minutes 58 seconds (9.965 minutes0

We are going to use the formula;

• Remaining amount = Original amount × 0.5^n

That is; N = N₀ ×  0.5^n , where n is the number of half lives.

n = 40 minutes ÷ 9.965 minutes

  = 4.014

Therefore;

N = 4 g × 0.5^4.014

 = 0.248 g

Therefore, the mass of Nitrogen-13 that will be left is 0.248 g