Visualizing a Chemical Reaction 2 Na 10 mole

Visualizing a Chemical Reaction 2 Na 10 mole Na ___ + Cl 2 5 mole Cl 2 ___ 2 Na. Cl 10 ? mole Na. Cl ___

Visualizing a Chemical Reaction 2 Na 10 mole Na ___ + Cl 2 5 mole Cl 2 ___ 2 Na. Cl 10 mole Na. Cl ___

Formation of Ammonia

Proportional Relationships 2 1/4 c. flour 1 tsp. baking soda 1 tsp. salt 1 c. butter 3/4 c. sugar 3/4 c. brown sugar 1 tsp vanilla extract 2 eggs 2 c. chocolate chips Makes 5 dozen cookies. I have 5 eggs. How many cookies can I make? 5 eggs 5 doz. 2 eggs Ratio of eggs to cookies 150 dozen cookies = 12. 5 Courtesy Christy Johannesson www. nisd. net/communicationsarts/pages/chem

Proportional Relationships • Stoichiometry – mass relationships between substances in a chemical reaction – based on the mole ratio • Mole Ratio – indicated by coefficients in a balanced equation 2 Mg + O 2 2 Mg. O Courtesy Christy Johannesson www. nisd. net/communicationsarts/pages/chem

Stoichiometry Steps 1. Write a balanced equation. 2. Identify known & unknown. 3. Line up conversion factors. – – – Mole ratio Molarratio mass Mole - Molarity Molar volume - moles grams moles liters soln moles liters gas Core step in all stoichiometry problems!! 4. Check answer. Courtesy Christy Johannesson www. nisd. net/communicationsarts/pages/chem

Molar Volume at STP 1 mol of a gas=22. 4 L at STP Standard Temperature & 0°C and 1 atm Courtesy Christy Johannesson www. nisd. net/communicationsarts/pages/chem Pressure

Molar Volume at STP LITERS OF GAS AT STP Molar Volume (22. 4 L/mol) MASS IN GRAMS Molar Mass (g/mol) 6. 02 1023 MOLES particles/mol NUMBER OF PARTICLES Molarity (mol/L) LITERS OF SOLUTION Courtesy Christy Johannesson www. nisd. net/communicationsarts/pages/chem

How many moles of KCl. O 3 must decompose in order to produce 9 moles of oxygen gas? 2 KCl. O 3 2 KCl + 3 O 2 ? mol 9 mol O 2 9 mol 2 mol KCl. O 3 3 mol O 2 x mol KCl. O 3 = 9 mol O 2 2 mol KCl. O 3 3 mol O 2 = 6 mol KCl. O 3 6 mol = 6 mol KCl. O 3 Courtesy Christy Johannesson www. nisd. net/communicationsarts/pages/chem

How many grams of KCl. O 3 are required to produce 9. 00 L of O 2 at STP? 2 KCl. O 3 2 KCl + 3 O 2 ? g 9. 00 L O 2 1 mol O 2 2 mol 122. 55 KCl. O 3 g KCl. O 3 22. 4 L O 2 3 mol O 2 x g KCl. O 3 = 9. 00 L O 2 1 mol O 2 22. 4 L O 2 1 mol KCl. O 3 = 32. 8 g KCl. O 3 32. 8 g 2 mol KCl. O 3 122. 55 g KCl. O 3 = 32. 8 g KCl. O 3 3 mol O 2 1 mol KCl. O 3 Courtesy Christy Johannesson www. nisd. net/communicationsarts/pages/chem

How many grams of silver will be formed from 12. 0 g copper? Cu + 2 Ag. NO 3 2 Ag + Cu(NO 3)2 12. 0 g Cu ? g 1 mol Cu 2 mol Ag 107. 87 g Ag 63. 55 g Cu 1 mol Ag x g Ag = 12. 0 g Cu = 40. 7 g Ag 2 mol Ag 107. 87 g Ag 1 mol Cu 1 mol Ag 63. 55 g Cu 1 mol Cu Courtesy Christy Johannesson www. nisd. net/communicationsarts/pages/chem 40. 7 g = 40. 7 g Ag

Mole Calculations A graduated cylinder holds 25. 4 cm 3 of mercury. If the density of mercury at 25 o. C is 13. 534 g / cm 3, how many moles of mercury are in the cylinder? How many atoms of mercury are there? HINT: Volume of solids/liquids and moles are not directly connected. You must first use the density to convert the volume to a mass, and then derive the quantity of mercury, in moles, from the mass. Finally, the number of atoms is obtained from the number of moles. x Volume, cm 3 g cm 3 use density x Mass, g Kotz & Treichel, Chemistry & Chemical Reactivity, 3 rd Edition , 1996, page 93 mol g use molar mass x Moles atoms mol use Avogadro’s number Atoms

A x Volume, cm 3 g cm 3 use density B x Mass, g C mol g x use molar mass Moles atoms mol use Avogadro’s number Atoms A Therefore, the mass of mercury is found to be equivalent to 344 g of mercury. 25. 4 cm 3 Hg. 13. 534 g Hg = 1 cm 3 Hg 344 g Hg B Knowing the mass, you can now find the quantity in moles. 344 g Hg. 1 mol Hg. = 200. 6 g Hg 1. 71 mol Hg C Finally, because you know the relation between atoms and moles (Avogodro’s number), you can now holds find the number atoms in Ifthe A graduated cylinder 25. 4 cm 3 ofofmercury. thesample. density of mercury at 25 o. C is 13. 534 g / cm 3, how many moles of mercury are in the cylinder? 23 there? How many atoms are 6. 02 x 10 atoms Hg. = 1. 03 x 1024 atoms Hg 1. 71 mol Hgof. mercury 1 mol Hg Kotz & Treichel, Chemistry & Chemical Reactivity, 3 rd Edition , 1996, page 93

2 Na + Cl 2 2 Na. Cl x. L 1 gram 100 2 grams g xg 2 grams WRONG Violates Law of Conservation of Matter 1 mol Na 2 1 molecule x atoms L Cl 2 = 100 g Na 23 g Na 2 moles 1 mole 1 mol Cl 2 222. 4 L Cl 2 molecules* = 4948. 69 L Cl. L 2 2 mol Na 1 mol Cl 2 2 moles Right side of room…calculate how many grams of Na. Cl will be produced from 100 g of Na. x g Na. Cl = 100 g Na 1 mol Na 23 g Na 2 mol Na. Cl 58. 5 g Na. Cl = 254 g Na. Cl 2 mol Na 1 mol Na. Cl Left side of room…calculate how many grams of Na. Cl will be produced from 48. 69 L of Cl 2. x g Na. Cl = 48. 69 L Cl 2 *Better name would be “formula unit” 1 mol Cl 2 22. 4 L Cl 2 2 mol Na. Cl 58. 5 g Na. Cl = 254 g Na. Cl 1 mol Cl 2 1 mol Na. Cl

Stoichiometry 2 KCl. O 3 2 KCl 500 g xg x L O 2 = 500 g KCl. O 3 x g O 2 = 137 L O 2 + 3 O 2 x. L (196 g) 3 mol O 2 22. 4 L O 2 1 mol KCl. O 3 137 LLO 2 = 137 122. 5 g KCl. O 3 2 mol KCl. O 3 1 mol O 2 32 g O 2 = 196 g O 2 22. 4 L O 2 1 mol O 2 x g KCl = 500 g KCl. O 3 2 mol KCl 74. 5 g KCl 1 mol KCl. O 3 (304 gg)KCl = 304 122. 5 g KCl. O 3 2 mol KCl. O 3 1 mol KCl

Stoichiometry 2 Ti. O 2 + 4 Cl 2 + 3 C 115 x gg x mol CO 2 + 2 CO + 2 Ti. Cl 4 4. 55 mol x molecules How many moles of chlorine will react with 4. 55 moles of carbon? x mol C = 4. 55 mol Cl 2 3 mol C 4 mol Cl 2 = 6. 07 mol Cl 2 How many grams of titanium (IV) oxide will react with 4. 55 moles of carbon? x g Ti. O 2 = 4. 55 mol C 1 mol Ti. O 2 80 g Ti. O 2 2 mol Ti. O 2 3 mol C = 243 g Ti. O 2 How many molecules of Ti. Cl 4 will react with 115 g Ti. O 2? x molecules Ti. Cl 4 = 115 g Ti. O 2 1 mol Ti. O 2 2 mol Ti. Cl 4 6. 02 x 1023 molecules Ti. Cl 4 1 mol Ti. Cl 4 80 g Ti. O 2 2 mol Ti. O 2 = 8. 66 x 1023 molecules Ti. Cl 4

Which has more atoms: 30 g aluminum metal or 18 m. L distilled water? How many atoms of aluminum are in 30 g of aluminum? 1 mol Al x atoms Al = 30 g Al 27 g Al 6. 02 x 1023 atoms Al = 6. 69 x 1023 atoms Al 1 mol Al 6. 02 x 1023 atoms Al x atoms Al = 30 g Al = 6. 69 x 1023 atoms Al 27 g Al How many atoms are in 18 m. L of water? WRONG H 2 O 23 molecules 3 atoms 6. 02 x 10 atoms H 2 O 1 mol H 2 O 6. 02 x 10 1 L H 2 O x atoms = 18 m. L H 2 O 1 molecule H 2 O 1 mol H 2 O 1000 m. L H 2 O 22. 4 L H 2 O LITERS is ONLY used for GASES @ STP How many atoms are in 18 m. L of water? 1 g H 2 O 1 mol H 2 O 6. 02 x 1023 molecules H 2 O x atoms = 18 m. L H 2 O 18 g H 2 O 1 mo. L H 2 O Recall, density of water = 1. 45 x 1021 atoms 3 atoms 1 molecule H 2 O = 1. 81 x 1024 atoms