# Mole Objectives Define mole Convert mole to number

Mole

Objectives: Define mole. Convert mole to number of particles.

Mole unit used to express amount of substance based on a certain number of particles

Dozen and Mole 1 dozen = 12 pieces 1 mole = 6. 02 x 1023 particles 1/2 dozen of apples = 6 apples ½ mole of C atoms = 3. 01 x 1023 C atoms 2 dozens of eggs = 24 eggs 2 moles of H 2 O molecules = 1. 20 x 1024 H 2 O molecules

Mole amount of substance containing the same number of particles as 12 g of C-12. 1 mole contains 6. 02 x 1023 particles (Avogadro’s number) Particles – may be atoms, molecules, ions

Check for Understanding 1. How many atoms are there in 1. 0 mole sample of Fe? 2. How many molecules are there in 2. 5 moles of CO 2?

Mole and Number of Particles 1 mole of any substance contains 6. 02 x 1023 particles (atoms, molecules, ions) 1 mole C-12 1 mole CO 2 6. 02 x 1023 atoms 6. 02 x 1023 molecules

Mole – Number of Particles Conversion x 6. 02 x 1023 particles/mole Mole Number of Particles Sample Problem 1: How many molecules are there in 0. 25 moles of H 2 O? 0. 25 mol H 2 O x 6. 02 x 1023 molecules H 2 O mol = 1. 505 x 1023 molecules H 2 O

Mole – Number of Particles Conversion Mole / 6. 02 x 1023 particles/mole Number of Particles Sample Problem 2: How many moles are there in 1. 2 x 1024 molecules of H 2 O? 1. 2 x 1024 molecules H 2 O = 2. 0 moles H 2 O x 1 mole H 2 O 6. 02 x 1023 molecules H 2 O

Do the following conversions: 1) 1. 8 x 1024 molecules NH 3 = _____ moles 2) 0. 75 moles Cl 2 = _____ molecules 3) 3. 0 moles Fe = _____ atoms 4) 3. 01 x 1023 ions of NO 3 - = _____ moles

Closure: Think-Pair-Share How many molecules are there in 3. 0 moles of CO 2? 1. Think about how you will go about answering this question. 2. With your group mates, figure out the answer to the question. 3. Make sure everyone in the group knows how to find the answer. 4. If your group is chosen and is able to show the class how to find the correct answer, you earn 3 extra

Check for Understanding 1. How many atoms are there in 1. 0 mole sample of Fe? 2. How many molecules are there in 2. 5 moles of CO 2? 3. What is 1. 806 x 1024 atoms of Cu in number of moles?

Molar Mass 1 mole C-12 1 mole CO 2 6. 02 x 1023 atoms 6. 02 x 1023 molecules 12 g 44 g

Molar Mass Molar mass – mass of 1 mole of a substance (in grams) - equals the total mass of all the atoms in a substance What is the molar mass of H 2 O? H O 2 moles 1 mole 2 (1 g) = 2 g 1(16 g) = 16 g 2 g+ 16 g = 18 g The molar mass of H 2 O is 18 g.

Molar Mass What is the molar mass of Mg(OH)2? Mg H O 1 mole 2 moles 1(24 g) = 24 g 2 (1 g) = 2 g 2 (16 g) = 32 g 24 g+ 2 g +32 g = 58 g The molar mass of Mg(OH)2 is 58 g.

Check for Understanding What is the molar mass of: 1. NH 3 2. Cl 2 3. Cu 4. KNO 3 5. Mg 3(PO 4)2

Closure: Write-Pair-Share 1. In your own words, describe how the molar mass of a substance is calculated. 2. Share your answer with your group mates. 3. Make sure that everyone in the group has the correct answer to the question. 4. If your group is chosen and is able to give the correct answer, you earn 2 extra credit point.

Objective: Do mass-mole conversions.

Mole –Mass Conversion / Molar Mass Mole x Molar Mass Sample Problem 1: What is the mass of 0. 25 moles of H 2 O? Mass of H 2 O = 0. 25 mol x = 4. 5 g 18 g mol

Mole –Mass Conversion / Molar Mass Mole x Molar Mass Sample Problem 2. How many moles are there in 36 g of H 2 O? Moles of H 2 O = 36 g x 1 mol 18 g = 2. 0 mol

Check for Understanding Do the following conversions: 1) 25 g NH 3 = _____ moles 2) 0. 75 g Cl 2 = _____ moles 3) 3. 0 moles Fe = _____ grams 4) 4. 5 moles KNO 3 = _____ grams

Closure: Write-Pair-Share 1. In your own words, describe how you can do mass to mole and mole to mass conversions. 2. Share your answer with your group mates. 3. Make sure that everyone in the group has the correct answer to the question. 4. If your group is chosen and is able to give the correct answer, you earn 3 extra credit points.

Vocabulary Review 1. Solution 2. Solute 3. Solvent 4. Dilute 5. Concentrated

Objectives 1. Define molarity. 2. Solve molarity problems. 3. Prepare a solution of a given molar concentration.

Molarity - unit of solution concentration - equal to number of moles of solute per liter (or dm 3) of solution Molarity = Mole of solute Liter of solution

Molarity 1. What is the molarity of a 2 L solution that contains 1 mole of solute? Molarity = = Mole of solute Liter of solution 1 mol 2 L = 0. 5 mol/L = 0. 5 M

Molarity 2. ) 29 g of Na. Cl is dissolved in enough water to make a 1 L solution. What is the molarity of this solution? Molarity = Mole of solute Liter of solution 29 g = = = X 1 mol 58 g 1 L 0. 50 mol/L 0. 50 M

Check for Understanding Solve these problems: 1. What is the molarity of a 3. 00 L solution that contains 4. 00 moles of solute? 2. If 18. 5 g of KCl is dissolved in enough water to produce 0. 5 L of solution, what is the molarity of the solution?

3. If 5. 00 g of KBr is dissolved in enough water to produce 500. 0 m. L of solution, what is the molarity of the solution?

Molarity 3. ) How many grams of Na. Cl is needed to produce 1. 0 L of a 0. 75 M solution? Molarity 0. 75 M = = Mole of solute Liter of solution Mole of solute 1. 0 L Mole of solute = Mass of solute = = 0. 75 mol/L x 1. 0 L = 0. 75 mol x 58 g/mol 43. 5 g = 44 g

Check for Understanding Solve this problem: 1. How many grams of KCl should be dissolved in water to produce 0. 50 L of a 1. 0 M solution?

Closure: Write-Pair-Share 1. Answer this question alone: How many grams of KI are needed to produce 1 L of 0. 25 M KI solution. 2. Share your answer with your group mates. 3. Make sure that everyone in the group has the correct answer to the question. 4. If your group is chosen and is able to give the correct answer, you earn 3 extra credit points.

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