Chapter 10 The Mole

The Mole: A Unit of Measure First, let’s look at a more familiar unit of measure: “dozen” 1 dozen = 12 1 dozen eggs = 12 eggs 1 dozen atoms = 12 atoms 1 dozen NaCl molecules = 12 NaCl molecules

Let’s try another familiar unit 1 dozen apples = 12 apples 1dozen apples = 2.0kg I dozen apples = 0.20bushel What is the mass of 90 average sized apples if one dozen apples has a mass of 2.0kg?

Calculations How many Toll House Chocolate Chip cookies will one bag of Nestle chocolate chips produce? “One bag of chocolate chips = 12 oz.” “12 oz of chocolate chips = 2 cups” “2 cups will provide 5 dozen cookies” “1 dozen = 12 cookies”

Chocolate Chip Cookies How many Toll House Chocolate Chip cookies will one bag of Nestle chocolate chips produce? One bag of chocolate chips = 12 oz. 12 oz of chocolate chips = 2 cups 2 cups will provide 5 dozen cookies 1 dozen = 12 cookies 1 bag x 12 oz. x 1 bag 2 cups x 12 oz. 5 dozen 2 cups x 12 cookies = 1 dozen 60 cookies

Units of Measure 1 mole = 602,000,000,000,000,000,000,000 (or 6.02 x 1023) 1 mole of eggs = 6.02 x 1023 eggs 1 mole of atoms = 6.02 x 1023 atoms 1 mole of H2O molecules = 6.02 x 1023 H2O molecules

Why use the mole? For easier calculations To compare the masses of different elements and compounds To predict how much of a product you will get from reactants in a chemical reaction

The Mole The number of representative particles in a mole is 6.02 X1023 It is also called Avogadro’s number Representative Particles Ionic compounds – Formula units Covalent (molecular compounds) – molecules Elements- atoms

Example Magnesium is a light metal used in manufacture of aircraft, automobile wheels, tools, and garden furniture. How many moles of magnesium is 1.25 X 1023 atoms of magnesium?

Converting moles to number of atoms Propane is a gas used for cooking and heating. How many atoms are in 2.12 mol of propane (C3H8)?

Molar Mass To calculate the molar mass of a substance: 1. Find the mass of each element 2. Multiply the mass by the number of atoms present in the compound 3. Then add the total masses of each element together

Molar Mass Example Glucose (C6H12O6) H2O

The Mole- Mass Relationship Use the molar mass of a substance to convert between mass and moles

Example The aluminum satellite dishes are resistant to corrosion because the aluminum reacts with oxygen in the air to forma coating of aluminum oxide. This tough resistant coating prevents any further corrosion. What mass of 9.45 mol of aluminum oxide?

Converting Mass to Moles example When iron is exposed to air, it corrodes to form red-brown rust. Rust is Iron (III) oxide. How many mole of iron(III) oxide are contained in 92.2 g of pure Fe2O3 ?

The Mole-Volume Relationship Avogadro’s hypothesis states that equal volumes of gases at the same temperature and pressure contain equal number of particles. Standard temperature and pressure

Mole to Volume Relationship STP (Standard temperature and pressure) 0 degrees Celsius 101.3kPa or 1atm At STP, 1 mol or 6.02X 1023 representative particles of any gas occupies a volume of 22.4L The quantity 22.4 L is called the molar volume of a gas

Example

Calculating Molar Mass from Molar Density Molar mass= density @ STP X Molar volume @ STP

Example

The mole road map