Respuesta :
Average atomic mass is the weighted average atomic masses with regard to the relative abundance of the isotopes
average atomic mass of Li = relative abundance of Li-6 x mass of Li-6 + relative abundance of Li-7 x mass of Li-7
average atomic mass of Li = (7.42% x 6.0151 a.m.u) + (92.58% x 7.0160 a.m.u)
= 0.446 + 6.495
= 6.941 amu
average atomic mass of Li is 6.941 amu
average atomic mass of Li = relative abundance of Li-6 x mass of Li-6 + relative abundance of Li-7 x mass of Li-7
average atomic mass of Li = (7.42% x 6.0151 a.m.u) + (92.58% x 7.0160 a.m.u)
= 0.446 + 6.495
= 6.941 amu
average atomic mass of Li is 6.941 amu
Answer: The average atomic mass of Lithium is 6.94 amu.
Explanation:
Mass of isotope Li-6 = 6.0151 amu
% abundance of isotope Li-6 = 7.42%= [tex]\frac{7.42}{100}=0.0742[/tex]
Mass of isotope Li-7= 7.0160
% abundance of isotope Li-7 = 92.58% = [tex]\frac{92.58}{100}=0.9258[/tex]
Formula used for average atomic mass of an element :
[tex]\text{ Average atomic mass of an element}=\sum(\text{atomic mass of an isotopes}\times {{\text { fractional abundance}})[/tex]
[tex]A=\sum[(6.0151\times 0.0742)+(7.0160\times 0.9258)][/tex]
[tex]A=6.94[/tex]
Therefore, the average atomic mass of Lithium is 6.94 amu.
