Question

a sample of 32 grams of unknown substances has a half life of 12 years. write an equation to determine the amount of substances (s) left after year T

Answer 1

Answer:

Nt = 32e^(-0.05775 t)

Step-by-step explanation:

ln (Nt/N₀) = -kt

Nt = mass of radioactive material at time interval (t)

N₀ = mass of the original amount of radioactive material

k = decay constant

t = time interval (t1/2 for the half-life)

ln (Nt/N₀) = -kt

N₁₂ = 16 gram

N₀ = 32 gram

t = 12

ln(1/2) = -12k

-0.693 = -12k

=> k = 0.05775

ln (Nt/N₀) = -0.05775 t

ln (Nt/32) = -0.05775 t

Nt/32 = e^(-0.05775 t)

=>Nt = 32e^(-0.05775 t)