Question

How many atoms are present in 2.50 grams of copper?

Answer 1

Answer:

5.9×10^20=158.875

Explanation:

mass of Cu = 2.501 g × 2.5% Cu/100 = 0.062525 g Cu

mass of Zn = 2.501 g × 97.5%/100 = 2.438475 g Zn

Calculate mol Cu: n = m/M; n = mole = ? mol; m = mass (g) = 0.062525 g Cu; M = molar mass (g/mol) = 63.546 g/mol Cun; Cu = 0.062525 g Cu/63.546 g/mol Cu = 0.00098393 mol Cu

Calculate the number of atoms of Cu:

1 mol atoms = 6.022×10^23 atoms

0.00098393 mol Cu × 6.022×10^23 atoms/mol = 5.9×10^20 atoms Cu to two significant figures

Calculate mol Zn:n = ? mol; m = 2.438475 g Zn; M = 65.39 g/mol Zn; n Zn = 2.438475 g Zn/65.39 g/mol Zn = 0.037291 mol Zn

Total number of atoms in a copper penny:

5.9×10^20 atoms

Answer 2

Answer:

158.875

Explanation:

not 100 percent sure let me know if its correct or not