I think it would be answer B or D . I gave you two answer because I dont want to be wrong with one
Answer:
Three half lives.
Explanation:
Given data:
Number of half lives passed = ?
Amount of parent isotope left = 12.5%
Solution:
At time zero = 100%
At 1st half life = 100%/2 = 50%
At second half life = 50%/2 = 25%
At third half life = 25%/2 = 12.5%
It means three half lives would passed.
Answer:
I’m not sure probably false
Explanation:
Answer:
The percent isotopic abundance of Cu-65 is 30.79 %.
The percent isotopic abundance of Cu-63 is 69.21 %.
Explanation:
we know there are two naturally occurring isotopes of carbon, Cu-63 (62.9298 amu) and Cu-65 (64.9278 amu)
First of all we will set the fraction for both isotopes
X for the isotopes having mass 62.9298 amu
1-x for isotopes having mass 64.9278 amu
The average atomic mass of copper is 63.546 amu.
we will use the following equation,
62.9298 x + 64.9278 (1-x) = 63.546
62.9298x + 64.9278 - 64.9278x = 63.546
62.9298x - 64.9278x = 63.546 - 64.9278
-1.998 x = -1.3828
x=-1.3828 / -1.998
x= 0.6921
0.6921 × 100 = 69.21 %
69.21 % is abundance of Cu-63 because we solve the fraction x.
now we will calculate the abundance of Cu-65.
(1-x)
1-0.6921 = 0.3079
0.3079 × 100 = 30.79 %
30.79 % for Cu-65.
Another name for them are called groups or families.
