If 82.5 g of potassium sulfide react, how many moles of K2S react

One mole of K2 S = 110.27g, so 3.3 moles K2 S = 363.89 g

First find the molar mass of K2 S:

K2 x 39.10 = 78.20

S1 x 32.07 = 32.07

78.20 + 32.07 = 110.27g

3.3 moles K2 S x 110.27g/mol = 363.89g