The answer to the question is a
Molar mass Cu(OH)₂ = 97.561 g/mol
97.561 g Cu(OH)₂ --------------- 6.02x10²³ atoms
? g Cu(OH)₂ -------------------- 9.1x10²⁵ atoms
mass = 9.1x10²⁵ * 97.561 / 6.02x10²³
mass = 8.87x10²⁷ / 6.02x10²³
mass = 14734.2 g
hope this helps!
The answer should be; 11
The atomic mass number is found by combining the number of protons and neutrons
Hope this helps :)