Lesson 1-2 and 3 The Mole and Stiochiometry.pptx

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1. Unit 1 Structure and Properties of Matter Lesson 1 The Mole Obj 1: Define an Avogadro’s number. Obj 2: Identify amount of substance in moles. Lesson 2 Mass and the Mole Obj 2: To Identify molar mass of elements in amu . Obj 1: To perform mass/ mole / particle conversions of elements . Lesson 3 Moles of Compounds Obj 1: To calculate molecular masses and formula units of compounds in amu . Obj 2: To perform mass/ mole / particle conversions of compounds.

2. Starter How many elements and atoms are in … H 2 O CaCO 3 Mg(NO 3 ) 2

3. Now, can you calculate the mass of each compound?

4. What is a pair of shoes? What is a dozen of eggs? Lesson 1 The Mole

5. What is a mole of eggs? 1 mole of eggs = 602,000,000,000,000,000,000,000 eggs!! This is 602 hexillion eggs Which is 6.02214076 × 10 23

6. The mole (mol) is the amount of a substance that contains as many elementary entities as there are atoms in exactly 12.00 grams of 12 C isotope. 1 mol = N A = 6.0221367 x 10 23 Avogadro’s number ( N A ) It is the number of particles (atoms) is one mole of any substance Avogadro’s number and molar mass

7. One Mole of: C S Cu Fe Hg

8. Lesson 2 Mass and The mole

9. Molar mass M is the mass of 1 mole of in grams eggs shoes marbles atoms 1 mole 12 C atoms = 6.022 x 10 23 atoms = 12.00 g 1 12 C atom = 12.00 amu 1 mole 12 C atoms = 12.00 g 12 C 1 mole lithium atoms = 6.941 g of Li For any element atomic mass (amu) = molar mass (grams)

10. 1 amu = 1.66 x 10 -24 g or 1 g = 6.022 x 10 23 amu 1 12 C atom 12.00 amu x 12.00 g 6.022 x 10 23 12 C atoms = 1.66 x 10 -24 g 1 amu M = molar mass in g/mol N A = Avogadro’s number The relationships between mass, mole and Avogadro's number

11. Example: Converting from moles to mass (in grams) What is the mass (in grams) in 1 mole of copper atom? 1 mol Cu = 63.55 g Cu 1 mole Cu 1 mol Cu 63.55 g Cu x = 63.55 g Cu 1 mol Cu 63.55 g Cu You need to chose between two conversion factors: OR 1 mol Cu 63.55 g Cu

12. Do You Understand Molar Mass? How many moles of He atoms are in 6.64 g of He ? Level 1

13. Do You Understand Molar Mass? How many grams of zinc are in 0.356 mole of zinc? Level 2

14. Do You Understand Molar Mass? How many atoms are in 16.3 g of sulfur? Level 3

15. x 6.022 x 10 23 atoms K 1 mol K = Do You Understand Molar Mass? How many atoms are in 0.551 g of potassium (K) ? 1 mol K = 39.10 g K 1 mol K = 6.022 x 10 23 atoms K 0.551 g K 1 mol K 39.10 g K x 8.49 x 10 21 atoms K Homework

16. https://padlet.com/mihadosman/i7qowwcotf9ab41j To conclude this .. A ‘molar mass’ of 1 mole of eggs = the masses of all eggs A molar mass of carbon = atomic mass of carbon A ‘molar mass’ of Lithium = the atomic mass of lithium What is the molar mass of a compound, such as CO2? (Share your thoughts in the link below)

17. Molecular mass (or molecular weight) is the sum of the atomic masses (in amu) in a molecule. For any molecule molecular mass (amu) = molar mass (grams) 1 molecule SO 2 = 64.07 amu 1 mole SO 2 = 64.07 g SO 2 Lesson 3 Moles of compounds

18. Calculate the molecular masses (in amu) of the following compounds: caffeine (C 8 H 10 N 4 O 2 ), a stimulant present in tea, coffee, and cola beverages Level 1: Example 3.5 C 8 H 10 N 4 O 2

19. Example 3.5 Strategy There are eight C atoms, ten H atoms, four N atoms, and two O atoms in caffeine, so the molecular mass of C 8 H 10 N 4 O 2 is given by 8(12.01 amu) + 10(1.008 amu) + 4(14.01 amu) + 2(16.00 amu) = 194.20 amu

20. Methane (CH 4 ) is the principal component of natural gas. How many moles of CH 4 are present in 6.07 g of CH 4 ? Level 2: Example 3.6

21. Example 3.6 Strategy We are given grams of CH 4 and asked to solve for moles of CH 4 . What conversion factor do we need to convert between grams and moles? Arrange the appropriate conversion factor so that grams cancel, and the unit moles are obtained for your answer.

22. Example 3.6 Solution The conversion factor needed to convert between grams and moles is the molar mass. First we need to calculate the molar mass of CH 4 , following the procedure in Example 3.5: The conversion factor we need should have grams in the denominator so that the unit g will cancel, leaving the unit mol in the numerator:

23. Example 3.6 We now write, Thus, there is 0.378 mole of CH 4 in 6.07 g of CH 4 . Check Should 6.07 of CH 4 equal less than 1 mole of CH 4 ? What is the mass of 1 mole of CH 4 ?

24. How many hydrogen atoms are present in 25.6 g of urea [(NH 2 ) 2 CO], which is used as a fertilizer, in animal feed, and in the manufacture of polymers? The molar mass of urea is 60.06 g. Challenging Question!! Example 3.7 Urea

25. Strategy We are asked to solve for atoms of hydrogen in 25.6 g of urea. We cannot convert directly from grams of urea to atoms of hydrogen. How should molar mass and Avogadro’s number be used in this calculation? How many moles of H are in 1 mole of urea? Challenging Question!! Example 3.7

26. Solution To calculate the number of H atoms, we first must convert grams of urea to moles of urea using the molar mass of urea. This part is similar to Example 3.2. The molecular formula of urea shows there are four moles of H atoms in one mole of urea molecule, so the mole ratio is 4:1. Finally, knowing the number of moles of H atoms, we can calculate the number of H atoms using Avogadro’s number. We need two conversion factors: molar mass and Avogadro’s number. Challenging Question!! Example 3.7

27. We can combine these conversions Check Does the answer look reasonable? How many atoms of H would 60.06 g of urea contain? Challenging Question!! Example 3.7

28. Formula mass is the sum of the atomic masses (in amu) in a formula unit of an ionic compound. Formula Mass For any ionic compound formula mass ( amu ) = molar mass (grams) 1 formula unit NaCl = 58.44 amu 1 mole NaCl = 58.44 g NaCl

29. Plenary Instructions: In pairs, roll the dice to pick a question to answer. How many moles are in the following. 10 g of Na 30 g of NaCl 45 g of Fe 35 g of NH 3 19 g of H 2 SO 4 60 g of CO 2