1) A sample of element X contents 100 atoms with a mass of 12. 00 u an 10 atoms with mass of 14. 00 u calculate the average atomic mass of element x.
1) A sample of element X contents 100 atoms with a mass of 12. 00 u an 10 atoms with mass of 14. 00 u calculate the average atomic mass of element x.
Dear student
The average atomic mass of an element is calculated by taking the weighted average of the atomic masses of its stable isotopes.
In other words, each stable isotope will contribute to the average mass of the element proportionally to its abundance.
avg. atomic mass=∑i(isotopei×abundancei)
To calculate an isotope's decimal abundance, you need to divide the number of atoms of that isotope by the total number of atoms present in the sample.
In your case, you know that the sample contains 100 atoms with an atomic mass of 12.00 u and 10 atoms with an atomic mass of 14.00 u.
The total number of atoms in the sample will thus be
100+10=110 atoms
The decimal abundances for the two isotopes will be
100atoms110atoms=0.90909→ for the first isotope
10atoms110atoms=0.090909→ for the second isotope
This means that the average atomic mass of the element will be equal to
avg atomic mas=12.00 u×0.90909+14.00 u×0.090909
avg. atomic mass = 12.18181 u
hope you understand
The average atomic mass of an element is calculated by taking the weighted average of the atomic masses of its stable isotopes.
In other words, each stable isotope will contribute to the average mass of the element proportionally to its abundance.
avg. atomic mass=∑i(isotopei×abundancei)
To calculate an isotope's decimal abundance, you need to divide the number of atoms of that isotope by the total number of atoms present in the sample.
In your case, you know that the sample contains 100 atoms with an atomic mass of 12.00 u and 10 atoms with an atomic mass of 14.00 u.
The total number of atoms in the sample will thus be
100+10=110 atoms
The decimal abundances for the two isotopes will be
100atoms110atoms=0.90909→ for the first isotope
10atoms110atoms=0.090909→ for the second isotope
This means that the average atomic mass of the element will be equal to
avg atomic mas=12.00 u×0.90909+14.00 u×0.090909
avg. atomic mass = 12.18181 u
hope you understand
