## Chemistry: A Molecular Approach (3rd Edition)

$45.9g\ K_{2}SO_{4}$
Divide the mass of the second reactant by its molar mass to find the moles of the second reactant. Multiply this by the mole ratio from the balanced chemical equation to get the moles of the first reactant. Finally, multiply the moles of the first reactant by the molar mass of the the first reactant to get the mass of the first reactant. $55.8g\ Sr(NO_{3})_{2}\times\frac{1mol\ Sr(NO_{3})_{2}}{211.6298g\ Sr(NO_{3})_{2}}\times\frac{1mol\ Sr(NO_{3})_{2}}{1mol\ K_{2}SO_{4}}\times\frac{174.2592g\ K_{2}SO_{4}}{1mol\ K_{2}SO_{4}}=45.9g\ K_{2}SO_{4}$