4. CalculationCalculation of Moles Moles Conc Vol

5. A mole is an amount of substance A dozen = 12 A gross = 144 A score = 20 A bakers dozen = 13 A million = 1.0 x 10 6 A mole = 6.022 x 10 23 602,200,000,000,000,000,000,000

6. + + For any reaction the right amount of each ingredient is essential + + 1 dozen eggs 1/6 dozen pints of milk 1/12 dozen bags of flour 2 dozen pancakes

7. 2 dozen molecules of H2H2 + 1 dozen molecules of O2O2 2 dozen molecules of H2H2 O OR 2 moles of molecules of H2H2 + 1 mole of molecules of O2O2 2 moles of molecules of O H2H2

8. H2H2 + O2O2 O H2H2 2 2 Number of moles = How much x How strong Number of moles = Mass you’ve got How much one mole weighs One mole = Relative mass (in grams) in a solution in a solid

9. H2H2 + O2O2 O H2H2 2 2 4 grams + 32 g 36 grams 1 1 1 1 1 1 16 1 1

10. H2H2 + O2O2 O H2H2 2 2 4 grams + 32 g 36 grams 1 1 1 1 1 1 16 1 1

11. 11 The molar mass is  the mass of one mole of a substance  the atomic mass of an element expressed in grams Molar Mass

12. 12 Give the molar mass to the nearest 0.1 g. A. K = ________ B. Sn = ________ Learning Check

13. 13 Give the molar mass to the nearest 0.1 g. A. K =39.1 g B. Sn =118.7 g Solution

14. 14 Molar Mass of CaCl 2  For a compound, the molar mass is the sum of the molar masses of the elements in the formula. We calculate the molar mass of CaCl 2 to the nearest 0.1 g as follows. ElementNumber of Moles Atomic MassTotal Mass Ca140.1 g/mole 40.1 g Cl235.5 g/mole 71.0 g CaCl 2 1 111.1 g

15. 15 Molar Mass of K 3 PO 4 Determine the molar mass of K 3 PO 4 to 0.1 g. ElementNumber of Moles Atomic MassTotal Mass in K 3 PO 4 K339.1 g/mole 117.3 g P131.0 g/mole 31.0 g O416.0 g/mole 64.0 g K 3 PO 4 1 212.3 g

16. 16 One-Mole Quantities 32.1 g 55.9 g 58.5 g 294.2 g 342.3 g

17. Guide to Calculating Molar Mass 17

18. Lets tie it together Why is one mole 6.022 x 10 23 ? So if we have 6.022x 10 23 atoms of Li it would have a mass of 6.941 grams. And if you have 6.022 x 10 23 atoms of F it would have a mass of 18.998 grams. Because magically if you have this exact number of atoms their total mass will equal the relative atomic mass in grams.

19. 19 Calculate the molar mass for Al(OH) 3 to the nearest 0.1g. 1) 44.0 g/mole 2) 75.0 g/mole 3) 78.0 g/mole Learning Check

20. One mole = RAM or GFM in grams and contains 6.022 x 10 23 particles So one mole of any substance will have a mass in grams equal to the sum of its atomic masses And one mole of molecules of any compound will have mass equal to it’s GFM – Eg 6.023 x 10 23 molecules of H 2 O will have a mass of 18 grams because it GFM is 18

21. If we have the equation: 2 H 2 + C CH 4 Molar ratio 2 : 1 : 1 This says 2 moles of Hydrogen molecules react with one mole of Carbon atoms We know now that 2 moles of Hydrogen molecules will have a mass of 4 grams. And we know that 1 mole of Carbon atoms will have a mass of 12 grams. So if we react 4 grams of hydrogen with 12 grams of carbon we get 1 mole of CH 4 One mole = RAM or GFM in grams and contains 6.022 x 10 23 particles

22. Number of moles = Mass of substance used Mass of 1 mole Number of moles = Mass of substance used Mass of 1 mole x

23. Calculate the mass of 0.1 mole of H 2 O Number of moles = Mass of substance used Mass of 1 mole x = 0.1 x 18g = 1.8g

24. Calculate the mass of… 3 moles of H 2 S 1 O 4 0.1 mole of CaCO 3 0.5 moles of NaCl