Given, mass of isotope 1 = 39.06 amu
% abundance of isotope 1 = 10.00%
mass of isotope 2 = 42.14 amu
% abundance of isotope 2 = 90.00%
Average atomic mass
= [ (mass of isotope 1 x % abundance of isotope 1 ) + (mass of isotope 2 x % abundance of isotope 2 ) ]/ 100
= [(39.06 x 10) + (42.14 x 90)]/100
= (390.6 + 3792.6) / 100
= 4183.2/100
= 41.8 (to the nearest tenth)
Therefore, the weighted atomic mass of element Q is 41.8 amu.
