• Support PF! Buy your school textbooks, materials and every day products Here!

Can someone please check this radiochemistry question please

  • Thread starter shenzys
  • Start date
  • #1
5
0

Homework Statement



A sample of sodium pertechnetate injection was found to have an activity of 51439 counts per minute (cpm). The sample was measured again exactly after 8 hours and found to have an activity of 20476 cpm. Calculate the half life of sodium pertechnatate.

Homework Equations



A = A0 e^-lamdat
ln A = in A0 - lamdat
half life = ln2/lamda

The Attempt at a Solution



ln 20476 = ln 51439 -lamda * 8
9.927008748 = 10.84815192 - lamda * 8
0.9150875487/8 = -lamda
lamda = 0.1143859436

half life = 6.06 hours

Is this correct? I think I did the algebra a bit wrong but the answer of 6 hours sounds about right... can anyone help please...thanks.
 

Answers and Replies

  • #2
5
0
Okay I went wrong... I now get the answer of 6.02 hours...
 

Related Threads for: Can someone please check this radiochemistry question please

  • Last Post
Replies
1
Views
1K
Replies
1
Views
1K
  • Last Post
Replies
21
Views
2K
Replies
5
Views
1K
Replies
3
Views
1K
  • Last Post
Replies
2
Views
2K
Top