Calculate the average atomic mass for the element beryllium, given this information about the relative abundance of its 3 isotopes.
Be-8 = 0.2% Be-9 = 98.9% Be-10 = 0.9%. Please show all your work.

Less Credit so, I won't able

 9.007

Explanation:

Be-8  8 x   0.20%  =0.016

Be-99 x98.90%=     8.901

Be-1010 x0.90%  =        0.09

        100.00%       9.007

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.