How to Calculate the Mass of 1μCi 241Am?

[jije1112]

Homework Statement

what is the mass in g of the activity?
(a)1μCi 241Am

Homework Equations

A = λN
λ = ln2 / T1/2

The Attempt at a Solution

A = λN

1μCi = λN

N=1μCi/λ

N = ( x /241 mol) × (6.022 × 1023 nuclei mol-1 )

1μCi/λ=( x /241 mol) × (6.022 × 1023 nuclei mol-1 )

X=1μCi (241)/λ(6.022× 1023)

λ = ln2 / T1/2

λ = ln2/ 432.2 yr

λ =5.09x10-11 S-1

X=1μCi (241)/( 5.09x10-11 )*(6.022× 1023)
x=2.4 x10^-7

there is something wrong!

 

[gleem]

N = ( x /241 mol) × (6.022 × 1023 nuclei mol-1 )

Why did you write this equation? Your previous equation is all you need. You want to find N and you know the activity and λ.

 

[gleem]

You need to know that 1 Ci is 3.7E10 disintegrating nuclei per sec.