How many moles of chloride ions are in 0.50 g of copper(II) chloride?
There are 0.0074 mol of Cl⁻ ions in 0.50 g of CuCl₂.
The formula tells you that there are 2 mol of Cl⁻ in 1 mol of CuCl₂. So we must find the moles of CuCl₂.
We must convert grams of CuCl₂ → moles of CuCl₂ → moles of Cl⁻
0.50 g CuCl₂ ×