Mole

1. Mole

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

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

4. Dozen and Mole 1 mole = 6.02 x 1023 particles ½ mole of C atoms = 3.01 x 1023 C atoms 2 moles of H2O molecules = 1.20 x 1024 H2O molecules 1 dozen = 12 pieces 1/2 dozen of apples = 6 apples 2 dozens of eggs = 24 eggs

5. 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

6. Check for Understanding • How many atoms are there in 1.0 mole sample of Fe? • How many molecules are there in 2.5 moles of CO2?

7. Mole and Number of Particles • 1 mole of any substance contains 6.02 x 1023 particles (atoms, molecules, ions) 1 mole C-12 6.02 x 1023 atoms 1 mole CO2 6.02 x 1023 molecules

8. 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 H2O? 0.25 mol H2O x 6.02 x 1023 molecules H2O mol = 1.505 x 1023 molecules H2O

9. Mole – Number of Particles Conversion Mole Number of Particles / 6.02 x 1023 particles/mole Sample Problem 2: How many moles are there in 1.2 x 1024 molecules of H2O? 1.2 x 1024 molecules H2O x 1 mole H2O 6.02 x 1023 molecules H2O = 2.0 moles H2O

10. Do the following conversions: 1) 1.8 x 1024 molecules NH3 = _____ moles 2) 0.75 moles Cl2 = _____ molecules 3) 3.0 moles Fe = _____ atoms 4) 3.01 x 1023 ions of NO3- = _____ moles

11. Closure: Think-Pair-Share How many molecules are there in 3.0 moles of CO2? 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 credit points.

12. Check for Understanding • How many atoms are there in 1.0 mole sample of Fe? • How many molecules are there in 2.5 moles of CO2? • What is 1.806 x 1024 atoms of Cu in number of moles?

13. Molar Mass 1 mole C-12 6.02 x 1023 atoms 12 g 1 mole CO2 6.02 x 1023 molecules 44 g

14. 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 H2O? H O 2 moles 1 mole 2 (1g) = 2g 1(16g) = 16g 2g+ 16 g = 18 g The molar mass of H2O is 18g.

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

16. Check for Understanding What is the molar mass of: 1. NH3 2. Cl2 3. Cu 4. KNO3 5. Mg3(PO4)2

17. 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.

18. Objective: • Do mass-mole conversions.

19. Mole –Mass Conversion / Molar Mass Mass Mole x Molar Mass Sample Problem 1: What is the mass of 0.25 moles of H2O? Mass of H2O = 0.25 mol x 18 g mol = 4.5 g

20. Mole –Mass Conversion / Molar Mass Mass Mole x Molar Mass Sample Problem 2.How many moles are there in 36 g of H2O? Moles of H2O = 36 g x 1 mol 18g = 2.0 mol

21. Check for Understanding Do the following conversions: 1) 25 g NH3 = _____ moles 2) 0.75 g Cl2 = _____ moles 3) 3.0 moles Fe = _____ grams 4) 4.5 moles KNO3 = _____ grams

22. 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.

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

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

25. Molarity • unit of solution concentration • equal to number of moles of solute per liter (or dm3) of solution  Mole of solute Molarity = Liter of solution

26. Molarity 1. What is the molarity of a 2 L solution that contains 1 mole of solute? 1 mol Mole of solute Molarity = = 2 L Liter of solution 0.5 mol/L = 0.5 M =

27. Molarity 2.) 29g of NaCl is dissolved in enough water to make a 1L solution. What is the molarity of this solution? 29 g X 1 mol Mole of solute Molarity = 58 g Liter of solution = 1 L 0.50 mol/L = 0.50 M =

28. 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?

29. 3. If 5.00 g of KBr is dissolved in enough water to produce 500.0 mL of solution, what is the molarity of the solution?

30. Molarity 3.) How many grams of NaCl is needed to produce 1.0 L of a 0.75 M solution? Mole of solute 0.75 M Mole of solute Molarity = = 1.0 L Liter of solution Mole of solute 0.75 mol/L x 1.0L = 0.75 mol = Mass of solute = 0.75 mol x 58 g/mol = 43.5 g = 44 g

31. 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?

32. 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.