Chapter 2 - Atoms and the Atomic Theory - Example 2-8 - Relating Number of Atoms, Amount in Moles, and Mass in Grams - Page 57: Practice Example A

248 g

Moles of Cu= $\frac{\text{Number of Cu atoms}}{\text{Avogadro number}}$ $=\frac{2.35\times10^{24}\,atoms}{6.022\times10^{23}\,atoms/mol}=3.90\,mol$ Mass of Cu= Moles of Cu$\times$Molar mass of Cu $=3.90\,mol\times63.546\,g/mol$ $=248\,g$