Answer:
824 g
Explanation:
First we convert 7.0 x 10²⁴ formula units of magnesium chloride (MgCl₂) into moles, using Avogadro's number:
There are two Cl moles per MgCl₂ moles, meaning that we have (2 * 11.62) 23.24 moles of Cl
Finally we convert 23.24 moles of chlorine into grams, using chlorine's molar mass: