Chemical Quantities Chapter 12

What do all these things have in common with the mole? 1 dozen1 pair1 six pack Answer: They all represent quantities Warm-up #1

Measuring Matter What is a mole?  The mole (mol) is the SI base unit used to measure the amount of a substance.  1 mol = 6.02x10 23 representative particles 6.02x10 23 is called Avogadro’s number  Representative particles are the units used in these conversions Particles Names Atoms, formula units (ionic compounds), molecules (covalent compounds)

Everything Leads to the Mole 1mole = 6.02 x particles1mole = molar mass 1mole = 22.4 L at STP

Mole to Particle Conversions How many molecules of water are there in 2.4 moles of water? How many moles of copper contain 3.5 x copper atoms? 1mole = 6.02 x particles

Warm-up #2 What is the mass of this bicycle given the mass of it’s individual parts? 1wheel = 0.5 kg, 1frame = 5 kg, 1seat = 0.2 kg, 1 set of handlebars = 1kg

Mass and the Mole The mass of one mole of a substance is unique to that substance and is based on the sum of the atomic masses of the elements in that substance. 1 mole of lead = 207.2g1 mole of water = 18.0g 1 mole of copper = 63.6g Mass of H 2 O = mass of two hydrogen atoms + mass of one oxygen atom

Calculating Molar Mass Elements The molar mass of elements is equal to their atomic mass from the periodic table. Example: 1 mole of Fe atoms = g Compounds The molar mass of compounds is equal to the sum of the atomic masses of the individual elements in that compound. Example: 1 mole of Fe 2 (SO 4 ) 3 = (2 x ) + (3 x ) + (12 x ) =

Mole-Mass Conversions Unlike mole-particle conversions where the conversion factor is always 1mole = 6.02 x particles, each mole- mass conversion factor is unique to the substance involved. Convert 2.3 moles of sodium (Na) to grams of Na Convert 10.0 g of CO 2 to moles of CO 2

Warm-up #3 What contains more representative particles, a mole of Fe 2 (SO 4 ) 3 or a mole of H 2 O?

Volume and the Mole According to Avogadro, the mass of one mole of a gas at STP is always 22.4L regardless of the gas’ identity. STP = Standard Temperature and Pressure (0 o C and 1 atm)

Mole-Volume Conversions How many moles of CO are contained in 1.8L of CO gas? How many Liters of SO 3 are represented by 0.5 moles of SO 3 gas?

Multi-Step Conversions 1mole = 6.02 x particles1mole = molar mass 1mole = 22.4 L at STP What is the mass of 1.0 x atoms of Aluminum?

Warm-up #4 Examine the reaction above. Using the parts below, how many of the product could be made? + 4

What is Stoichiometry? Stoichiometry is the study of quantitative relationships between amounts of reactants used and products formed by a chemical reaction.

Practical Applications of Stoichiometry In a spacecraft, the carbon dioxide exhaled by astronauts can be removed by its reaction with lithium hydroxide, LiOH, according to the following chemical equation. CO 2 (g) + 2LiOH(s) Li 2 CO 3 (s) + H 2 O(l) How many moles of lithium hydroxide are required to react with 20 mol of CO 2, the average amount exhaled by a person each day?

Strategy – Relate everything to the mole The mole is the common thread that links reactants to products. 1CO 2 (g) + 2LiOH(s) 1Li 2 CO 3 (s) + 1H 2 O(l) Mole Ratios

Mole Super Highway

Stoichiometry Practice Problems 2H 2 (g) + O 2 (g) 2H 2 O(l) How many moles of water can be formed from 3 moles of oxygen? How many grams of water can be formed from 8.0 grams of hydrogen gas at?

Warm-up #5 Ingredients 2 1/4 cups all-purpose flour 1 teaspoon baking soda 1 teaspoon salt 1 cup (2 sticks) butter, softened 3/4 cup granulated sugar 3/4 cup packed brown sugar 1 teaspoon vanilla extract 2 large eggs 2 cups (12-oz. pkg.) 1 cup chopped nuts Yield: 24 cookies How many cookies can be made if I only have 1 stick of butter and 1 cup of sugar (and the exact quantity of the other ingredients in the recipe)?