posted by Sarah .
A nickel has a mass of 5.000 grams and is composed of 25% nickel and 75% copper. What is the mass of copper in the nickel? How many moles of copper are in this nickel? How many copper atoms are in this nickel?
mass Cu = 5.000 x 0.75 = ??
moles Cu = mass Cu/molar mass Cu.
There are 6.022 x 10^23 Cu atoms in a mole of Cu atoms.