STOICHIOMETRY Chapter 9: Pages 298-327

Cooking with Chemistry The Balanced Equation! If we want to know how to make a product, how do we know the “recipe” for making that product?

Two Types of Stoichiometry Composition Stoichiometry – the conversions between mass, moles, particles, and liters of a substance. Reaction Stoichiometry – the conversions between reactants and products in a chemical reaction.

Concept Base You must know how to Balance equations Calculate molar mass for any substance Convert moles into grams using molar mass Convert moles into particles using 6.02 x 1023 Interpret the meaning of a balanced equation

Interpreting Equations NO! 2C(s) + O2 ® 2CO(g) 2 mole C + 1 mole O2 ® 2 mole CO 2 atoms C + 1 molecule O2 ® 2 molecules CO 2 g C + 1 g O2 ® 2 g CO NO!!!

Coefficients Coefficients represent mole ratios particle ratios (and even the ratio of Liters for some gases as we will see later) BUT NEVER mass ratios.

2C(s) + O2(g) ® 2CO(g) Q1: How many moles of CO are produced from the reaction of 2 moles of C with an excess of O2? A1: 2 moles CO Q2: How many moles of CO are produced from the reaction of 1 mole of C with an excess of O2? A2: 1 mole CO

2C(s) + O2(g) ® 2CO(g) A3: 3.56 mol CO Q3: How many moles of CO are produced from the reaction of 3.56 mol of C with an excess of O2? A3: 3.56 mol CO Q4: How many moles of CO are produced from the reaction of 2.50 mol of O2 with an excess of C? A4:

2C(s) + O2(g) ® 2CO(g) Q5: How many grams of C are used in the reaction to produce 3.00 moles of CO? A5: 2 2 = 36.0 g C

2C(s) + O2(g) ® 2CO(g) Q6: How many grams of C are used in the reaction to produce 9.8 grams of CO? A6: = 4.2 g C

2C(s) + O2(g) ® 2CO(g) Q7:How many grams of O2 are used in the reaction to produce 1.24 x 1024 molecules of CO? molecules CO ® molecules CO ® mol CO molecules CO ® mol CO ® mol O2 molecules CO ® mol CO ® mol O2 ® g O2 = 33.0 g O2

2C(s) + O2(g) ® 2CO(g) Q8: How many molecules of O2 are used in the reaction to produce 3.4 moles of CO? A8: 1.0 x 1024 molecules O2 Q9: How many atoms of C are used in the reaction to combine with 3.6 g of O2? A9: 3.8 x 1022 atoms C

You Try It. Do the Stoichiometry Worksheet #1.