Question

If we start with 1.000g of strontium 90 0.953 grams will remain after 2.0 years (a) what is the half life of strontium 90 (b) how much strontium 90 will remain after 5.00 years Please show the necessary step

Answer 1

a) 29.0 years

b) 0.89 g

Step-by-step explanation:

Using the formula

t1/2= t×ln2/ln(No/Nt)

Where

Nt= mass of radioactive isotope at time= t =0.953g

No= initial mass of radioactive isotope present= 1.000g

t= time taken for N mass of radioactive isotope to remain = 2 years

t1/2 = half-life of radioactive isotope= ???

Substituting the values

t1/2= 2 × ln2/ln(1.000/0.953)

t1/2= 2× 0.693/0.048

t1/2= 29 hours

b)

N= No(1/2)^t/t1/2

Where t= 5 years

N= 1.000(1/2)^5/29

N= 1.000(1/2)^0.17

N= 0.89g