Limiting Reagent - reagent completely consumed in a reaction reagent - a substance or mixture for use in chemical analysis or other reactions
- determines the maximum amount of product formed
Steps:
- Identify the limiting reagent (by determining the # of moles of each reaction)
- Calculate the amount of product from the limiting reagent
Examples:
What mass of hydrogen is produced when 19.62g of zinc is reacted with 18.96g of hydrochloric acid
Zn(s) + 2 HCl(aq) -> ZnCl(aq) + H(g)
19.62g 18.96g
n_Z$$_n = m_Z$$_n / M_Z$$_n = 19.62g / 65.39 g / mol = 0.300688178 mol
n_H$$_C$$_l = m_H$$_C$$_l / M_H$$_C$$_l = 18.96g / 36.46 g / mol = 0.520021941 mol
# moles HCl needed = 0.300688178 mol Zn * 2 mol HCl / 1 mol Zn = 0.60376357 mol
Limiting reagents have to be 1 of the reactants
Homework (Grade 11 Chemistry) p.309 # 31 - 39, 7 - 12 p.311 # 40 - 50 p.313 # 1 - 11