there are 5 naturally occurring isotopes of the element zinc. the relative abundance and mass of each are as follow
64
30zn=48.89% 63.929 amu
66
30zn=27.81% 65.926
67
30zn=4.11% 66.927
68
30zn = 18.57% 67.925
70
30zn = 0.62% 69.925
find the average atomic mass of zinc
is it 0.4889(63.929)+0.2781(65.926) ....and then divide by 5 or 1?i am not sure .
divide by the sum of the abundances, 1.0
To find the average atomic mass of zinc, you need to consider the relative abundance and mass of each isotope. Here's how you can calculate it:
1. Multiply the abundance of each isotope by its mass number.
- For the first isotope, 63.929 amu, multiply 0.4889 (48.89%) by 63.929.
- For the second isotope, 65.926 amu, multiply 0.2781 (27.81%) by 65.926.
- Continue this process for the remaining isotopes.
2. Sum up the results of the multiplications from step 1 to get the total.
3. Divide the total from step 2 by 100 to account for the relative abundance percentages.
4. The result is the average atomic mass of zinc.
Let's calculate it:
(0.4889 * 63.929) + (0.2781 * 65.926) + (0.0411 * 66.927) + (0.1857 * 67.925) + (0.0062 * 69.925) = X
X / 100 = Average Atomic Mass of Zinc
Performing the calculations:
(0.4889 * 63.929) + (0.2781 * 65.926) + (0.0411 * 66.927) + (0.1857 * 67.925) + (0.0062 * 69.925) = 65.37
65.37 / 100 = 0.6537 amu
Therefore, the average atomic mass of zinc is approximately 0.6537 amu.