If you are given a aluminium sphere with a mass of 0.0679kg and its atomic number and mass number which is 13 and 26.982 respectively.The question is how many electrons in kg of a sphere?

Answer 1

I assume you mean how many electrons in 0.0679 kg? Or why else have that number.

0.0679 kg Al (1000 grams/1 kg)(1 mole Al/26.982 grams)(6.022 X 10^23/1 mole Al)

= 1.5 X 10^24 atoms

------------------------------------now

you were given that number 13 for a reason. that many electrons in aluminum

1.5 X 10^24 atoms Al * 13 electrons per atom Al

= 1.97 X10^25 electrons in mass of aluminum ( might call it 2.0 X 10^25 )