1. Moles and Stoichiometry Chapters 11 & 12

2. Counting Particles Particles are counted in moles Types of representative particles Atoms- smallest unit of an element Molecule- smallest unit of a molecular compound Formula Unit- smallest unit of an ionic compound

3. What is a Mole? 1 dozen = 12 of anything 1 gross = 144 of anything 1 ream = 500 of anything 1 mole = 6.02 x 10 23 of anything

4. Why? Atoms are inconceivably small Avogadro’s Number- 6.02 x 10 23 is the number of carbon-12 atoms in 12g

5. Understanding Reactions N 2 + 3H 2  2NH 3 1 molecule of nitrogen and 3 molecules of hydrogen produce 2 molecules of ammonia 1 mole of nitrogen molecules and 3 moles of hydrogen molecules produce 2 moles of ammonia molecules

6. Counting Particles Moles → Particles (multiply by Avogadro’s number) Example: how many atoms are there in 3 moles of aluminum? Particles → Moles (divide by AN) Example: How many moles are there in 5.71x10 27 formula units of calcium chloride?

8. Mass and the Mole MM (molar mass)- mass of 1 mole of representative particles in a compound or element Converting Between Moles and Grams Grams → Moles (divide by molar mass) Example: How many moles are there in 135.2 g of water? Moles → Grams (multiply by MM) Example: How many grams are there in 3.46 moles of calcium carbonate?

9. Chapter 12- Stoichiometry Stoichiometry- using chemical formulas to determine molar and mass relationships from balanced chemical equations

10. The Mole Ratio

11. All Roads go Through Moles Calculations between mass and particles are possible by first calculating the number of moles

13. Percent by Mass (Percent Composition) Remember? What is the percent composition of each element in sodium phosphate?

14. Determining an Empirical Formula Empirical Formula- lowest whole number ratio of elements in a compound Use % composition and assume 100g Divide by MM of each element to get moles Divide all by lowest number of moles Multiply to get the lowest whole number ratio Record empirical formula Example: a compound is determined to be 36.4% nitrogen and 63.16% oxygen, what is the empirical formula?

15. Determining a Molecular Formula Molecular Formula- multiple of empirical formula that accurately shows number of each atom Calculate mass of empirical formula (EFM) Divide MM of the compound by the EFM Multiply empirical formula by result Record molecular formula Example: A compound has a molar mass of 110.0 g/mol. What is the molecular formula if it is 65.45% C, 5.45% H, and 29.09% O?

16. Practice 1. Sulfuric acid reacts with sodium hydroxide in a double replacement reaction. If you start with 5.25 moles of NaOH, how many moles of water can you make? 2. If you start with 11.34 grams of NaOH, how many moles of sodium sulfate can you make? 3. If you start with 55.1 grams of NaOH, how many grams of sodium sulfate can you produce?

17. The End of a Long Road... Limiting Reagents Percent Yield