STOICHIOMETRY

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 = 16.5 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

Molar Volume Volume is the amount of space a material occupies Volume is traditionally measured in liters. 1 Liter is half the size of a 2 Liter soda bottle. If you had 6.02x1023 particles of O2, in a balloon, what would the volume of the balloon be? All gases have the same volume per mole: 22.4 L/mol So if you have 6.02x1023 gas particles, you have 1 mole, and your balloon would be 22.4 Liters or about 12 soda bottles.

C6H12O6 + 6O2 → 6CO2+ 6H2O ( + Energy in the form of ATP) The basic process of cellular respiration by which your body converts food energy into stored energy is given above. What volume in liters of CO2 would be produced if 450 grams of glucose was reacted with excess O2? How many grams of glucose would be needed to react completely with 122 liters of O2?

You Try It. Do the Stoichiometry Worksheet #1.