Here's how to calculate the grams in 5.2 moles of magnesium sulfide (MgS):

1. Find the molar mass of MgS:

* Magnesium (Mg) has a molar mass of 24.31 g/mol

* Sulfur (S) has a molar mass of 32.07 g/mol

* Molar mass of MgS = 24.31 g/mol + 32.07 g/mol = 56.38 g/mol

2. Use the conversion factor:

* 1 mole of MgS = 56.38 grams of MgS

3. Calculate the mass:

* 5.2 moles of MgS * (56.38 grams MgS / 1 mole MgS) = 293.58 grams of MgS

Therefore, there are approximately 293.58 grams in 5.2 moles of magnesium sulfide.