If 300.0g of NaN3 (Sodium Azide) is combined with 300.0g Pb(CH3O2)2 (Lead acetate) which compound runs out first?
Write the equation and balance it.
Convert 300.0 g NaN3 to moles. moles = grams/molar mass
Convert 300.0 g lead acetate to moles.
Using the coefficients in the balanced equation, convert moles of each to moles of the product. The moles of product will be different which means one of them is wrong; the correct answer in limiting reagent problems is ALWAYS the smaller one and the reagent producing the smaller number of moles of the product is the limiting reagent. That will be the one that is used completely.