Final answer:
The isotope Cu-63 has a mass of 62.9296 amu. The percent composition of copper isotopes is calculated using the mass and abundance of Cu-63 and Cu-65, which are 69.17% and 30.83% respectively. An estimated 10^22 Cu atoms are present in a 5.00 g sample of copper.
Step-by-step explanation:
The mass of the isotope Cu-63 is 62.9296 amu (atomic mass units) as measured on the atomic scale. This value is used to calculate the average atomic mass of naturally occurring copper, which is obtained by considering the weighted average of the masses of its two stable isotopes: Cu-63 and Cu-65, with their respective natural abundances. The average atomic mass of copper is 63.546 amu, where the abundance of Cu-63 is 69.170% and the remaining percentage is for Cu-65. The mass ratio of Cu-63 to Cu-65 is 1.0318, with their atomic masses being 62.9296 amu and 64.9278 amu respectively. Therefore, to calculate the percent composition of copper isotopes, the mass and abundance of each isotope are used. Considering the provided sample mass of 5.00 g of copper, which is approximately one-tenth of one mole of copper, a reasonable estimate for the number of Cu atoms in the sample would be on the order of 1022 atoms.