What is the atomic mass of copper (Cu)?
A. 27.0
B. 63.5
C. 29.0
D. 58.9

According to the internet it is around 63.5, Choice B.

Explanation:

Why would someone need to memorize this?

did anyone actually do this? like if anyone has submitted this i rly need .

  the   balanced   equation   for   reaction of   ca metal   with   o2 to   produce   cao   is as below

2 ca+ o2→ 2 cao2

  explanation

the reaction is   balanced     since the   number of atoms   in reactant side is   equal to   number of atoms   in   product side.   for   example   they   are 2   atom of   ca in   reactant   side   and   2   atoms of ca   in   the product side.

  the   process   is a   meet the   requirement   of   redox   reaction because :     calcium   is   oxidized   from   oxidation state 0   to 2+   while   oxygen   is reduced from   oxidation   state   0   to 2-