Question

How many chloride ions are in the following? 0.25 mol MgCl2
Show in significant figures

Answer 1

0.50 moles of chloride ions in 0.25 moles of MgCl2.

To find the number of chloride ions in 0.25 moles of MgCl2, you can use the information that one mole of MgCl2 contains two moles of chloride ions (Cl-).

So, for 0.25 moles of MgCl2:

Number of chloride ions = 0.25 moles × 2 (moles of Cl- per mole of MgCl2)

Number of chloride ions = 0.50 moles

However, it's important to note that when counting entities, like ions, you typically don't use significant figures. Instead, you use the exact conversion factor, which in this case is that one mole of MgCl2 contains two moles of Cl- ions. So, there are exactly 0.50 moles of chloride ions in 0.25 moles of MgCl2.