Limiting Reagent and Percent Yield

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Limiting Reagent and Percent Yield

N2(g) + 3H2(g) → 2NH3(g) The mole ratio is 1:3:2 If we have 1 mole of N2 and 6 moles of H2 what is the limiting reagent? What is the excess reagent?

Excess reagent – the reactant that is present in more that he required amount for a complete reaction Limiting reagent – the reactant that is completely consumed in a chemical reaction

To solve these problems use the mole bridge
Remember: Only moles can cross Specifically only the original mole can cross And to cross you need to multiply or divide

You need a 1:1 comparison to decide who crosses!
0.75 mol of Iron react with 0.6 mol of oxygen to form iron(III)oxide. How many moles of iron(III)oxide form? 4Fe O → Fe2O3 0.75 mol 0.60 mol X mol You need a 1:1 comparison to decide who crosses!

4Fe O → Fe2O3 0.80 mol 0.60 mol X mol

4Fe O → Fe2O3 0.85 mol 0.60 mol X mol

Percentage Yield Yield - the quantity of product produced in a chemical reaction IE what you get from the reaction

Two kinds of yield: Actual Yield: what is actually produced or what you can measure after the reaction Theoretical yield: the amount you calculate based on the balanced equation

Theoretical Yield 4Fe + 3O2 → 2Fe2O3
M = g/mol g/mol g/mol 10.00 g 10.00 g Theoretical Yield?

Theoretical Yield 4Fe + 3O2 → 2Fe2O3
M = g/mol g/mol g/mol 10.00 g 10.00 g Theoretical Yield = g

Percentage Yield The theoretical yield for a reaction is g and the actual Yield is g. What is the %yield?

So what? Environment: Money Chemical waste Is connected to
Poor yielding reactions Money