Presentation on theme: "II. Stoichiometry in the Real World * Limiting Reagents"— Presentation transcript:
1 II. Stoichiometry in the Real World * Limiting Reagents More Stoichiometry!II. Stoichiometry in the Real World * Limiting Reagents
2 X A. Limiting Reactants Available Ingredients 4 slices of bread 1 jar of peanut butter1/2 jar of jellyLimiting ReactantbreadExcess Reactantspeanut butter and jelly
3 X Jam Sandwich Equation 2 loaves bread + 1 jar of jam 20 sandwiches Mole Ratio 2 : 1 : 20What would happen if we had 1 loaf of bread and 1 jar of jam?Bread = limiting reactantJam = excess reactant (1/2 jar left)Produce 10 sandwiches
4 Limiting Reactantused up in a reactiondetermines the amount of productExcess Reactantadded to ensure that the other reactant is completely used upcheaper & easier to recycle
5 Example 1 2 Fe (s) + O2 (g) 2 FeO (s) Iron burns in air to form a solid black oxide (FeO). If you had 50.0 g of iron and 60.0 g of oxygen, what is the limiting and excess reactant? How much iron oxide could be produced?2 Fe (s) + O2 (g) 2 FeO (s)
6 2 Fe (s) + O2 (g) 2 FeO (s) mass = 50 g mass = 50 g mass = 60 g
7 Example 2 Zn + 2HCl ZnCl2 + H2 79.1 g mass = ? 0.90 L 2.5M 79.1 g of zinc react with 0.90 L of 2.5M HCl. Identify the limiting and excess reactants. How many grams of zinc chloride would be produced?Zn HCl ZnCl H279.1 g0.90 L2.5Mmass = ?
8 Zn HCl ZnCl H2mass = 79.1 gV = 0.90 L of 2.5Mmass = ?
9 Example 2 Results Limiting reactant: HCl Excess reactant: Zn Product Formed: x g ZnCl2left over zinc
10 Student Example CaCO3 + 2 NaCl CaCl2 + Na2CO3 Sodium carbonate is needed in the manufacturing of glass, but very little occurs naturally. It can be made from the double replacement reaction between calcium carbonate and sodium chloride. If you had 5.00 g of each what is the limiting and excess reactant? How much sodium carbonate would be formed?CaCO NaCl CaCl2 + Na2CO3
16 When 45. 8 g of K2CO3 react with excess HCl, 46. 3 g of KCl are formed When 45.8 g of K2CO3 react with excess HCl, 46.3 g of KCl are formed. Calculate the theoretical and % yields of KCl.K2CO3 + 2HCl 2KCl + H2O + CO245.8 g? gactual: 46.3 g