1. How do you find how many moles are in a certain amount of particles? Divide by Avogadro’s Number Example: How many moles are in 3.56 x 10 21 molecules of water? (3.56 x 10 21 ) ÷ (6.02 x 10 23 ) = 0.00591 or 5.91 x 10 -3 mol H 2 O Reminder= always a good idea to put numbers in parentheses when putting them in a calculator

2. How do you measure the amount of moles in a solid? Find the mass of the chemical (in grams) and divide by the molar mass Example: How many moles are in 0.13 grams of carbon? Molar mass of carbon= 12.0g 0.13 ÷ 12.0g = 0.011 mol C

3. How do you measure how many moles are in a gas? Use a simple fact: 1 mole of most gases occupy 22.4 Liters of space* * This number is really only an estimate and the potential to be very off. We will learn a more complicated way of finding out moles of gas per liter later This is true of most gases. So to calculate moles from Liters of a gas, divide by 22.4 Example: There is a balloon with 3.2 Liters of Helium in it. How many moles of Helium are there? Answer: 3.2 ÷ 22.4 = 0.14 mol He

4. Learning Checks! 1. How many moles are in 3.65 grams of NaCl (s) ? 2. How many moles are in 0.0150 L of CO 2(g) ? 3. How many moles are in 4.21 x 10 26 molecules of CO 2 ? 4. If you add 3.4 L of pure Nitrogen gas (N 2 ) into your tire, how many grams will your tires increase in mass by?

5. How do you measure the amount of moles in a liquid? One way: If the liquid is all of one pure substance, treat it like a solid and divide by its mass in grams by the molar mass Example: How many moles are in 20.0grams of methanol? (CH 4 O) Molar mass of CH 4 O = 32.0g/mol 20.0g ÷ 32.0 = 0.625 moles CH 4 O

6. 2 nd way: If it is NOT a pure substance, and is a chemical dissolved in water, then you must know the substances MOLARITY How do you measure the amount of moles in a liquid? Molarity is how many moles per liter you have of a substance Multiply by the Molarity to find moles Abbreviation = M Example: How many moles of NaOH do I have if I have 4ml of a 0.5 molar solution of NaOH dissolved in water? Answer = 0.004 x 0.5 = 0.0002 or 2 x 10 -4 mol NaOH Usually the measurement of liquids is in mL. You must divide by a 1000 to get Liters

7. Learning Checks! 5. How many moles are in a 3 M solution of acetic acid if you have 3 liters? 6. How many liters would you use if you wanted 0.50 mol of sulfuric acid if it was a 2 M solution? 7. What is the molarity of a substance that you have 3 moles dissolved in 250ml? 8. Which one has more particles (moles) in it? 10.0 grams solid I (iodine) or 0.0100 Liters I 2 gas or A 100. mL solution of 1.00M I.

8. 8. Which one has more particles (moles) in it? 10.0 grams solid I (iodine) or 0.0100 Liters I 2 gas or A 100. mL solution of 1.00M I. 9. 15ml of 0.5 Molar solution of HCl has how many moles of HCl in it? 10. If you had 10 grams of NaOH, and you dissolve it in 355ml of water, what is the molarity of the solution you made?

9. If you burn 1 mole of Carbon C + O 2  CO 2 How many moles of O 2 will you use, and how many moles of CO 2 will you get? Converting moles to moles requires the mole ratio

10. In the reaction: C 3 H 8 + O 2  CO 2 + H 2 O If you burn 3 moles of C 3 H 8, how many moles of CO 2 will you produce?

11. Learning Check CaC 2 + H 2 O --> Ca(OH) 2 + C 2 H 2 11. If you have 0.15 mol of H 2 O, how many moles of C 2 H 2 will you get? C 2 H 6 + O 2  CO 2 + H 2 O 12If you burn 3 moles of C 2 H 6, how many moles of CO 2 will you produce? 13. If I produced 0.055 mol of CO 2, how many moles of oxygen did I use? 14. If 45 moles of water was made, how many moles of CO 2 was also made?