K. Knippel Chemistry Aldine HS Limiting Reactants K. Knippel Chemistry Aldine HS
S’Mores…yummmm How many S’Mores can I make with…? 6 graham crackers 8 pieces of chocolate 10 marshmallows 4 pieces of chocolate What ingredient is limiting my number of s’ mores????
Another demo- magnesium strip, boys to girls…
Limiting Reactant In a chemical reaction, one reactant will run out before the other. We call this the limiting reactant. The limiting reactant determines how much product will be created. What were the limiting reactants with the s’mores??
In chemical reactions… These chemical reactions we have been studying have limiting reactants as well. Look at this reaction: C + O2 CO2 2 carbon atoms + + 3 carbon dioxide molecules 5 carbon atoms 3 oxygen molecules
SiO2 + 4HF SiF4 + 2H2O If 2.0 mol of HF are exposed to 4.5 mol of SiO2, which is the limiting reactant? Balance List what you know Choose 1 product to find mols/grams for Reactant that gives the least product is limiting reactant
SiO2 + 4HF SiF4 + 2H2O 4.5 2.0 ? mol mol mol 2.0 mol HF 1 mol SiF4 = 0.50 mol SiF4 *least 1 4 mol HF 4.5 mol SiO2 1 mol SiF4 = 4.50 mol SiF4 1 1 mol SiO2
__Fe + __H2O __Fe3O4 + __4H2 When 36.0g of H2O is mixed with 167g of Fe, what is the limiting reactant? How much Fe3O4 (in grams) will be produced?
__MgCl2 + __LiBr ????? I have 5.7 grams of LiBr and 2.4 grams of MgCl2. Which is the limiting reactant? What mass of MgBr2 will be produced?