1 Conserving Matter Read Conserving Matter: p.153 Do the Reading Guide- tape it into your CB when it is complete!

2 Warm Up- Make sure your reading guide is complete and taped in you CB.

3 C.2 Accounting for Atoms The law of conservation of matter says that “matter is neither created nor destroyed”.

4 Chemical Equations In a chemical reaction, the number of atoms of each element needs to be the same on both sides of the arrow. Reactants Products CH 4 + O 2  CO 2 + H 2 O

5 Balancing an Equation CH 4 + O 2  CO 2 + H 2 O a. Count the atoms on each side of the equation. b. Place coefficients in front to make the sides equal. c. Recheck to make sure it worked

6 Try these! a.NH 3  H 2 + N 2 b.CaCO 3  CaO + CO 2 c. HCl + Ca(OH) 2  CaCl 2 + H 2 O

7 How do I read a chemical equation? CaCO 3  CaO + CO 2 One formula unit of calcium carbonate reacts to form one formula unit of calcium oxide and one molecule of carbon dioxide. One mole of calcium carbonate reacts to form one mole of calcium oxide and one mole of carbon dioxide.

8 Work on the balancing equations WS

9 The Mole 6.02 X 10 23

10 Read C.5, p.161

11 The mole is a unit of measure Developed because it is impossible to work with individual atoms or molecules.

12 The Mole A counting unit Similar to a dozen (except instead of 12, it’s 602 billion trillion 602,000,000,000,000,000,000,000) 6.02 X particles/mole (in scientific notation) Amedeo _____________ (1776 – 1856)This number is named in honor of Amedeo _____________ (1776 – 1856), who studied quantities of gases and discovered that no matter what the gas was, there were the same number of molecules present

13 Just How Big is a Mole? Enough soft drink cans to cover the surface of the earth to a depth of over 200 miles. If you had Avogadro's number of unpopped popcorn kernels, and spread them across the United States of America, the country would be covered in popcorn to a depth of over 9 miles. If we were able to count atoms at the rate of 10 million per second, it would take about 2 billion years to count the atoms in one mole.

14 Where Did it Come From? It was NOT just picked! It was MEASURED. One of the better methods of measuring this number was the Millikan Oil Drop Experiment Since then we have found even better ways of measuring using x-ray technology

15 You must know… A mole of anything = 6.02 x particles Look! I have a bunch of samples for you to look at! It took me all break to count all these particles!

16 Look at the periodic table! The atomic mass of each element is written below the element symbol. The units on atomic mass are grams per mole (g/mol) So we have a bunch of conversion factors for doing cool calculations!

17 Conversion Flow Chart

18 Convert 1.Convert 6.17g of carbon to moles 2.Convert 2.3g Na to moles 3.Convert 0.05 moles of Cl to grams.

19 Warm Up Convert the following: a. 3.4 g of nitrogen to moles b. 0.72mol of fluorine to grams c g of magnesium to moles.

20 Molar Mass The molar mass of a compound is the sum of the atomic masses of all the atoms in the compound.

21 Find the Molar Mass of Calcium Chloride CaCl 2 The process 1.List how many atoms of each element? 2.Determine the atomic mass of each element. 3.Multiply by the number of atoms 4.Add them up!

22 You learned to do this last semester ! Calculate the molar mass of carbon dioxide? CO 2

23 Now try dinitrogen tetroxide N 2 O 4 Remember the process 1.How many atoms of each element? 2.What is the atomic mass of each element. 3.Multiply by the number of atoms 4.Add them up!

24 How did you do? N 2 O 4 2 Nitrogen x = g/mol 4 Oxygen x 16.0 = g/mol 1 mole of N 2 O 4 = g/mol

25 More Practice! Do C.6 in your CB p. 163

26 Convert the following 1.6.2g of NaCl to moles g of water to moles mol to water to grams

27 Moles and Mass WS Work on the WS… Change the #5 to just say CuSO 4 (Cross out the 5H 2 O)

28 Conversions using Avagadros Number How many atoms in 1.2 moles of Cu? How many atoms in 0.5 moles of Carbon? How many atoms in 1.3 mol of Li?

29 Going backwards How many moles in 3.2 x atoms of C? How many moles in 5.6 x atoms of F? How many moles in 5.6 x molecules of water?

30 The Mole and Avagadros number WS Work on the WS…

31 Going all the way! How many atoms in 0.30g of Lithium? How many molecules in 3.7g of water?

32 How many grams in 4.31 x atoms of Cu?