The mass of a proton is approximately 1836 times greater than that of an electron if the mass of a neutron is the same as that of a proton approximately how many atoms are in a 1-kg mass of copper?

Answer 1

Most of the information in the question is not needed in order to answer it; this is the sort of thing that some teachers do to trap their students. tut tut!

You need to know the Atomic Mass of copper, which is ~ 63.55. This tells you that the gram-atomic-mass (GAM) of copper is 63.55 grams. You have 1000gm of copper (and that is the only info you need from the question.)

1000/63.55 ~=15.7. So, you now know that you have 15.7 GAMs of copper.

The last thing you need is something called Avogadro's number. Named after the chemist who first measured it, this is the number of atoms in one GAM. The number is ~6 x 1023 . Therefore 15.7 x 6 x 1023 ~= 9.4 x 1024 atoms.

Answer 2

The atomic mass of copper is approximately 63.55 grams/mol. To find the number of copper atoms in 1 kg of copper, first convert 1 kg to grams (1000 g). Then, divide the mass of copper by its atomic mass to find the number of moles. Finally, use Avogadro's number (6.022 x 10^23) to convert moles to atoms. The approximate number of copper atoms in 1 kg of copper is about 3.35 x 10^24 atoms.