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Ch 3.3 and Ch 9 Scientific Notation—great for very large or very small numbers Ex 1: Hope Diamond has 460,000,000,000,000,000,000,000 atoms Ex 2: 1 Carbon atom of the Hope Diamond has a mass of 0.00000000000000000000002 g ◦ 4.6 x 1023 atoms = Hope Diamond atoms (not 45 x 1022) ◦ 2 x 10-23 grams = carbon atom mass 4.6 and 2 are the coefficients of the number The 10 to the raised power represents the number of decimal places 1. 2. 3. 4. 5. 6. 3,000,000,000 4500 0.000023 438,000 0.00245 0.056 3x109 4.5x103 2.3x10-5 4.38x105 2.45x10-3 5.6x10-2 (2.3 x 103)(8.2 x 104) = (7.34 x 10-5)(8.221 x 10-2) = 9 x 106 ÷ 4.00 x 103 = 6.23 x 103 + 2.5 x 105 = Think on this…do you need to write down EVERY single number the calculator gives you??? ◦ Sig figs! Meter for length Second for time Kilogram for mass (1 kg = 2.2 lbs) Mole for the amount of substance ◦ Use a meterstick to measure ◦ Weight is NOT the same thing as mass! ◦ Use a scale to measure Kelvin for temperature ◦ K = oC + 273 ◦ 0 K = absolute zero ◦ Use a thermometer to measure ◦ oC is another option, but not Fahrenheit (in the metric system) ◦ Use a stopwatch to measure ◦ We will talk about mole next chapter Liter for volume joule or calorie for energy ◦ Use a graduated cylinder to measure ◦ We don’t discuss this much in this class… Conversion factors ◦ Values can often be expressed in more than one form $1 = 4 quarters = 10 dimes = 20 nickels = 100 pennies 1 meter = 100cm = 1000mm = 0.001km ◦ equal values can be shown as a ratio equal to 1; such ratios are called conversion factors… $1 1000m 1km 60min 10 dim es 1hr 1km 1000m conversion factors are useful for solving problems in which given measurements must be expressed in some other unit. Dimensional Analysis: a way to problem solve/calculate that uses conversion factors to solve problems. Calculate how many seconds old you are? If you can run the 100 m dash in 12.72 seconds, how many kilometers per hour is that? Ex: Convert 1,000 kilometers into millimeters. Ex: A boat is to be three hundred cubits long, fifty cubits wide and thirty cubits high. How big is that in feet? ◦ HINT: 1 cubit = 45 cm; 1 foot = 30 cm How many minutes are there in one week? How many seconds are in one year? It takes 12 ounces of sugar to make 1 batch of cookies. How many batches of cookies can be made from a 5 pound bag of sugar? Ch 3.3 and Ch 9 We live in a quantitative world… ◦ ◦ ◦ ◦ How How How How much do you make? old are you? long is this class? many questions are on the final exam? How much? How many? We measure by COUNT, MASS, and/or VOLUME. 1 pair of shoes = 2 shoes 12 cupcakes =1 dozen cupcakes 1 reem of paper = 500 sheets Each of these could be used as a conversion factor If there are 800 students at LACHSA, how many dozen are there? Calculate it! MOLES is a unit like these…it represents a certain number!! 1 mole = 6.022 x 1023 of anything Moles are handy when there are large quantities of matter. ◦ What if you needed to count the number of grains of sand in 10 grams??? 1 mole of apples = 602,200,000,000,000,000,000,000 apples ◦ Thank goodness for scientific notation! 1 mole of $$ = $6.022 x 1023 1 mole of cheerios = 6.022 x 1023 cheerios A mole is 6.02 x 1023 of anything! A mole of basketballs would just about fit into a ball bag the size of the Earth! So just how big is a mole? Draw a 1 inch square box on your paper: When the teacher says “go” put as many dots in that box as you can in 30 seconds. Now, count the dots. (A highlighter or differently-colored pen may be useful.) x2, What is your dot making rate in dots/minute? _____________ Working at this rate, how many dots could you make in an hour? _____________________ If a student can make 303 dots per minute, it will take 3.78 x 1015 years to make a mole of dots! Even if 25 students in the class worked at this rate, it would take the class 1.51 x 1014 years, making dots 24-7, to make a mole of dots! 6.022x1023 is referred to as Avogadro’s Number 1 mole of Fe atoms = 6.022 x 1023 atoms 1 mole CO2 molecules= 6.022x1023 molecules 1 mol NaCl molecules= 6.022x1023 molecules Why the different units for Fe vs. CO2 vs NaCl?? 1 mole of carbon = 12.0 grams 1 mole of Fe = 55.9 g 1 mole of S = 32.1 g/mol Look at a periodic table, where are these numbers coming from? for our purposes, we will round to 1 decimal place for each atomic mass Atomic mass= mass of 1 mole of the atom Molar mass= atomic number = g/mol Unit can be g or g/mol 1. What is the mass of 1 mole of any element? it’s atomic mass 2. Where do you find it? Periodic table…(decimal value) 3. What is its unit of measurement? Grams or grams/mol To find the mass of 1 mole of a compound, you must know the formula of the compound. Molar masses of chemical compounds = the sums of the molar masses of all the atoms in one molecule of that compound. Ex: calculate the molar mass of 1 mole of carbon dioxide. Calculate the mass of 1 mole of Sodium Chloride (salt) ◦ ◦ ◦ ◦ ◦ ◦ Gotta know the formula: NaCl Na = 23.0 g x 1 atom in the compound = 23.0 g Cl = 35.5 g x 1 atom in the compound = 35.5 g Total = 23.0 + 35.5 = 58.5 g The molar mass of NaCl = 58.5 g 1 mole of NaCl = 58.5 g 1. Calculate the molar mass of water. 18.0 g/mol 2. Calculate the mass of 1 mole of PCl3. 137.5 g/mol 3. Calculate the molar mass of Zn(NO3)2. 189.4 g/mol Pg 84 Mass g molar mass 1mole 1 mole molar mass Mole 1mol _ 6.022x1023 atoms 6.022x1023 atoms 1mole # of Particles (atoms, molecules) Use to convert between mole and mass and amount of particles Pg 84 molar mass (g) = 1 mol Mass g Mole # of Particles 1 mol = 6.022x1023 particles (atoms, molecules) Use to convert between mole and mass and amount of particles When we convert moles to: molecules, atoms, formula units, etc, we use the following conversion factors: 23 1mol 1mol 23 6 . 02 x10 atoms 6 . 02 x10 atoms How many molecules are in 2.00 moles of sucrose? 2.00 moles x 23 6 . 02 x10 atoms 1mol = 1.20x1024 molecules 23 1mol 1mol 23 6 . 02 x10 atoms 6 . 02 x10 atoms How many moles are in 2.33 x 1024 molecules of water? 3.87 moles How many atoms are in 2.95 moles of Au? 1.77 x 1024 23 1mol 1mol 23 6 . 02 x10 atoms 6 . 02 x10 atoms Warm up: Correct intro to mole worksheet Correct HW Practice gram to mole Practice gram to particle Chalk activity Pg 84 molar mass (g) = 1 mol Mass g Mole # of Particles 1 mol = 6.022x1023 particles (atoms, molecules) Use to convert between mole and mass and amount of particles We use molar mass as a conversion factor: molar mass 1mol 1mol molar mass Ex: grams to moles Calculate the number of moles in 75.0 g dinitrogen trioxide. Calculate the number of moles in 75.0 g dinitrogen trioxide. 1. Find molar mass of N2O3 2. Use conversation factor 14.01x2 + 16.00x3 = 76.02g/mole 75.0g x 1 mole 76.02g = .986mol N2O2 The molar mass can be used to convert between mass and moles. Need to be able to go both ways…from moles to mass or mass to moles. You need 3.0 moles of NaCl for a lab experiment. ◦ How are you going to measure out 3.0 moles? Can’t do it on a scale… ◦ You need to convert from moles to grams. In order to convert, you need to know the mass of 1 mole of NaCl Now solve… 1. Calculate the mass, in g, of 0.250 moles of sodium chloride. 14.36 g 2. Calculate the number of moles in 75.0 g of nitrogen gas. How much is ONE mole of ◦ ◦ ◦ ◦ ◦ ◦ ◦ ◦ Zinc Water (H2O) NaCl Chromium Magnesium Sodium Bicarbonate Hydrogen peroxide carbon Mole song Boseman: https://www.youtube.com/watch?v=Pft2CASl 0M0 https://www.youtube.com/watch?v=xPdqEX_ WMjo Pg 84 molar mass (g) = 1 mol Mass g Mole # of Particles 1 mol = 6.022x1023 particles (atoms, molecules) Use to convert between mole and mass and amount of particles 1. How many molecules are in 1.14 moles of SO3? (6.87 x 1023 atoms) 1. Calculate the mass in grams of 2.50 moles of Iron (II) Hydroxide. (Who remembers how to write this formula???) (225 grams) 3. If you have 7.31 grams of CuSO4, how many moles is this? ◦ (0.0458 moles) 4. How many moles are in 4.65 x 1023 molecules of NO2 Is this a 1 step or 2 step problem??? (0.772 moles) Pg 84 Mass g molar mass 1mole 1 mole molar mass Mole 1mol _ 6.022x1023 atoms 6.022x1023 atoms 1mole # of Particles (atoms, molecules) Use to convert between mole and mass and amount of particles Pg 84 Mass g 1 mol = molar mass Mole # of Particles 1 mol = 6.022x1023 (atoms, molecules) Use to convert between mole and mass and amount of particles 1. Find the mass, in grams of 4.52 x 1023 molecules of C20H42? ◦ (212 grams) 2. Find the number of atoms in 75.0 g of dinitrogen trioxide? ◦ Molar mass = 76.0g/mol, ◦ 5.94x1023 atoms 3. How many grams are there in 2.80 x 1024 atoms of silicon? ◦ Don’t forget your sig.figs! ◦ 4.65x28.1g = 131g 4. How many grams is 2.7 x 1023 molecules of Br2? 71.6 = 72g 1. How many molecules are in 1.14 moles of SO3? (6.87 x 1023 molecules) 2. Calculate the mass in grams of 2.50 moles of Iron (II) oxide. 179.8 g 3. How many grams are there in 2.80 x 1024 atoms of N2? ◦ Don’t forget your sig.figs! ◦ 4.65x28.1g = 131g Turn in warm ups and Mole worksheet! How many moles are there in 2.80 x 1024 atoms of silicon? ◦ Don’t forget your sig.figs! How many moles is 2.7 x 1023 molecules of Br2? NOTICE: how we calculated for atoms when talking about an element and molecules when talking about a compound? ◦ Can you calculate atoms for a compound? Could you calculate atoms of Br2? ◦ YES, but that is not a single step problem… ◦ …see next slide Often multiple conversion factors are needed. ◦ Like if you need to convert your age to seconds… ◦ Go from years to months to days to hours to sec. 1. How many ATOMS of propane (a covlnt cmpd!!) are in 2.12 moles of propane (C3H8)? ◦ Why can you NOT go straight from moles to atoms in this problem? 23 24 C H molecules 6.02x10 molecules = 1.28x10 3 8 2.12 moles x 1mol 11 atoms per molecules (1.28x1024) x 11 = 1.40 x1025 atoms 2. How many ATOMS of Carbon are in 2.12 moles of propane (C3H8)? 23 24 C H molecules 6.02x10 molecules = 1.28x10 3 8 2.12 moles x 1mol 11 atoms per molecules 3/11 of atoms are C (1.28x1024) x 11 = 1.40 x1025 atoms 3/11 (1.40 x1025 ) = 3.84 1024 C atoms 3. How many molecules are in 1.14 moles of SO3? (6.87 x 1023 molecules) 4. How many atoms are in 1.14 moles of SO3? (2.75 x 1024 atoms) 5. How many atoms are in 1.09 x 1024 molecules of water? 6. How many atoms of hydrogen in 2,560 atoms of water? 7. How many atoms of hydrogen in 1.50 moles of water? 1. 2. 3. 4. What is the molar mass of 1 mole of lithium? What is the molar mass of 1 mole of carbon dioxide? What is molar mass of 35 grams of .5 mole of aluminum? What is the molar mass of 10 moles of sodium that has a mass of 220 grams. 1. 2. 3. 4. How many moles are in 32.58 g of H2O? How many molecules are in 1.808 moles of H2O? How many atoms are in 1.09 x 1024 molecules of water? What is the mass in grams of 7.23 x 1023 molecules of sucrose (C12H22O11)? 1. 2. How many atoms of oxygen in 3.00 moles of carbon dioxide? How many atoms of hydrogen in 20.0 grams of H4CO Volume (L) 22 . 4 L 1mol 1mol 22 . 4 L The MOLE 1mol 1mol molar mass 6 . 02 x10 6 . 02 x10 Mass (g) 23 1mol molar mass 1mol atoms 23 atoms Molecules, atoms, formula units Volume L 1 mole 22.4 L Mass g molar mass 1mole 1 mole molar mass Pg 84 22.4 L 1 mole Mole 1mol _ 6.022x1023 atoms 6.022x1023 atoms 1mole # of Particles (atoms, molecules) Pg 84 Volume L 22.4 L = 1 mole Mass g 1 mol = molar mass Mole # of Particles 1 mol = 6.022x1023 (atoms, molecules) For gases, Avogadro (in 1811) proposed a significant relationship that stated that: equal volumes of gases at the same temperature and pressure contain equal numbers of particles. ◦ Particle size varies for different gases but because particles are so spread out, they do not take up any greater amount of space. Temp has an effect on volume ◦ As temp. increases, volume increases Pressure also has an effect on volume ◦ As pressure increases, volume decreases STP = Standard Temperature and Pressure ◦ Temp = 0 degrees C & pressure = 1 atm MOLAR VOLUME = 22.4 L/mol (the volume of one mole of a gas) One mole of ANY gas will expand to have a volume of 22.4 L at STP. STP = Standard Temperature and Pressure ◦ Standard Temp: 0 degrees C ◦ Standard Pressure: 1 atm The conversion factors (always): 22 . 4 L 1 mol 1 mol 22 . 4 L 1. How many moles of N2 are in 120 L of gas? 120L x 1mol = 5.36 mol N2 22.4L Can you then calculate the mass? Pg 84 Volume L 22.4 L = 1 mole Mass g 1 mol = molar mass Mole # of Particles 1 mol = 6.022x1023 (atoms, molecules) 2. What is the volume of 2.54 moles of methane gas? ◦ 56.9L 3. How many moles are in 6.00 L of H2 gas? .268mol .3mol 4. How many grams are in 12 L of O2 gas? 17.1g= 17g 5. How many L of oxygen gas (at STP) are in 6.5 x 1024 molecules of oxygen gas? 242L = 240 L Density= mass/ volume or D= g/L 6. The density of a gas at STP is 0.901 g/L. What is the molar mass of the gas? 0.901 g x L 22.4 L 1 mole = 20.2 g/mol 7. What gas is it? neon 8. What is the density of 1.00 mole of helium gas? 4.00 g/mol x 1mol/22.4 L = .179 g/L Follow the road map! Moles L or L moles: molar volume 22 . 4 L 1 mol 1 mol 22 . 4 L Moles g or g moles: molar mass molar mass 1mol 1mol molar mass 0.6 moles of SO2 is produced when coal is burned. How many liters of gas at STP is this? At STP, what volume does 1.25 moles of He occupy? 74.5 liters of CO2 at STP is contained in a flask. How many moles is this? The density of a gas at STP is 1.964 g/L. What is the molar mass of the gas? What is the density of krypton gas at STP? In your Chemistry Notebook, classwork sections: Create your own molar road map including pictures and conversation factors. Be creative and use color. Include the following: Title Moles (in the middle) Particles Mass Volume Arrows between each unit (3 total) Conversion factors between each unit (3 total) A picture to represent each unit (4 total) Color for emphasis End day 1. 2. At STP, what volume does 1.75 moles of He occupy? 39.2L What would be the volume of 8.00g of helium of STP? 44.8L 3. What is the density of He at STP? 4.0g/mol x 1mol/22.4L = .179g/L The recipe of chemistry Suppose you are preparing a cake. Each Cake (Ck) requires 1.0 cake mix (Cm), 0.5 cup of oil (Oi), 1.0 cup of water (Wa) and 2.0 eggs (Eg). Write the balanced equation for making: 1 ________ + 0.5 ________ + 1________ 2 _______ 1 ________ 1.0 cake mix + 0.5 cups oil + 1.0 cup water + 2 eggs 1.0 cake How much is left over? 7 1 1.0 cake mix + 0.5 cups oil + 1.0 cup water + 2 eggs 1.0 cake Calculate the number of cakes (Ck) that can be made from 12 cake mixes (Cm) ◦ 12Cm x 1 Ck 1 Cm = 12 Ck Calculate the number of cakes (Ck) that can be made from 10.0 cups of oil (Oi) ◦ 10.0 Oi x 1 Ck = 20 Ck 0.5Oi If you need to make 29 cakes (Ck), how many eggs (Eg) do you need? ◦ 29 Ck x 2 Eg 1 Ck = 58 Eg Stoichiometry: the calculation of quantities in chemical reactions Equations are a chemist’s recipe. ◦ Eqs tell chemists what amounts of reactants to mix and what amounts of products to expect. When you know the quantity of one substance in a rxn, you can calculate the quantity of any other substance consumed or created in the rxn. Nearly everything we use is manufactured from chemicals. ◦ Soaps, shampoos, conditioners, CD’s, cosmetics, medications, clothes. For a manufacturer to make a profit the chemical processes carried out in industry must be economical A balanced equation is needed and used so chemicals are not wasted when making products How would you read: ◦ N2 (g) + H2 (g) NH3 (g) Balance and read: ◦ N2 (g) + 3H2 (g) 2NH3 (g) ◦ Coefficients can represent different possible units Atoms/molecules Moles Mass in grams Mass of reactants equals mass of products Law of Conservation of mass Liters (if compound is a gas at STP) N2 + 3H2 1 mol N2 + 3 mol N2 28.0 g N2 22. 4L 22.4 L N2 2NH3 2 mol NH3 + 3 (2.0 g H2) 2 (17.0 g NH3) 34.0 g 34.0 g reactants products + 22.4 L 22.4 L 22.4 L 67.2 L H2 22. 4L 22. 4L 44.8 L NH3 ◦ What are the possible mole ratios in: N2 (g) + 3H2 (g) 2NH3 (g) ◦ 1 mole of N2 reacts with 3 moles of H2 to produce 2 moles of NH3. ◦ Possible mole ratios for this formula: 1N2 3H2 1N2 2NH3 3H2 2NH3 Reaction to form ammonia in this 1:3:2 ratio. Mole ratios are CONVERSION FACTORS! Once you have the ratios, you can perform calcs. (a.k.a. STOICHIOMETRY) Amount of given (mol) Mole ratio: from balanced equation Amount of X Mole unknown = Mole given unkown (mol) Ex: How many moles of water are produced from 5.80 moles of oxygen gas? O2 + H2 H2O O + 2H 2H O 1. Write equation 2. Balance! 3. Set up conversion factor 2 2 5.80mole O2 x 2 2 mol H2O 1 mol O2 11.6 moles water 1. How many moles of ammonia are produced from 0.60 moles of N2? ◦ (1.2 mol NH3) 2. How many moles of H2 are needed to react with 0.43 moles of N2 gas? ◦ (1.29 mol H2) 3. How many moles of H2 are needed to produce 1.98 moles of ammonia (NH3)? ◦ (2.97 mol H2) Amount of given (mol) Mole ratio: from balanced equation X Mole unknown = Mole given Amount of unkown (mol) 4. Ammonia, NH3 is a widely used fertilizer and used in household cleaners. How many moles of ammonia are produced when 6 mol of H gas react with excess nitrogen gas? 4 mol NH3 5. The decomposition of potassium chlorate, KClO3 into potassium chloride and oxygen gas is used as a source of oxygen in the lab. How many moles of potassium chlorate are needed to produce 15 mol of oxygen gas? 1. Write equation 2. Balance! 3. Set up conversion factor 10 mol KClO3 Historical Chemistry: pg 303, #1-2 End day Sn + 2HF SnF2 + H2 1. How many moles of SnF2 will be produced by 12.5 moles of HF? 1. How many moles HF are needed to produce 6.85 moles of SnF2? No lab balance measures moles directly, instead grams is a more practical unit. To calculate grams: 1. convert to moles first, then grams ◦ Using our same example, you can calculate how many grams of each compound: N2 (g) + 3H2 (g) 2NH3 (g) REMEMBER: when you use a gram/mole conversion factor: mol = molar mass 3.00 g N2 x 1 mol 28g x 2 mol NH3 1 mol N2 x 17 g 1 mol 1 Particle A Mass A Volume A 6.022x1023 Molar Mass 22.4 L 6.022x1023 Particle B Mole A Mole Ratio Mole Molar B Mass 22.4 L Mass B Volume B Ex 1: What mass, in grams, of glucose is produced when 3.00 mol of water reacts with excess carbon dioxide to produce glucose and oxygen? 6CO2 + 6H2O C6H12O6 + 6O2 1. Write equation 1 mol glucose 180.2g 3.00mol x x 2. Balance! 6 mol water 1 mole 3. Set up conversation factor 90.1g glucose Particle A Mass A Volume A 2. 6.022x1023 Molar Mass Mole A 6.022x1023 Particle B Mole Ratio 22.4 L Mole Molar B Mass Mass B 22.4 L Volume B What mass of carbon dioxide is needed to react with 3.00 mol water? 132g CO2 6CO2 + 6H2O C6H12O6 + 6O2 2. How many moles of H2O are formed from a reaction using 824g NH3 is the reaction: NH3 + O2 NO + H2O (unbalanced) 4NH3 + 5O2 4NO + 6H2O 72.5 mol H2O Particle A Mass A Volume A 6.022x1023 6.022x1023 Particle B Mole A Molar Mass Mole Ratio Mole Molar B Mass Mass B 22.4 L 22.4 L Volume B Ex 4: How many grams of SnF2 are produced from the reaction of 30.00g HF with Sn. Sn(s) + 2HF(g) SnF2(s) +H2(g) 30.00g HF x 1 mol HF 20.0 g HF x 1 mol SnF2 2 mol HF x 156.7g SnF2 1 mol SnF2 117.5g SnF2 5. How many grams of NH4NO3 are required to produce 33.0g N2O? (the laughing gas needed for an anesthetic in dentistry) 60.0g NH4NO3 NH4NO3(s) N2O(g) + 2H2O(l) 6. How many molecules of oxygen gas are produced when 29.2 g of water is decomposed? (4.88 * 1023 molecules of O2) 1. Carbon dioxide is produced from the synthesis of oxygen gas with carbon monoxide. Write and balance this chemical equation and then tell how many liters of oxygen gas are required to burn 3.86 liters of carbon monoxide. Assume STP. ◦ (1.93 L O2) 2. How many grams of NH4NO3 are required to produce 33.0g N2O? (the laughing gas needed for an anesthetic in dentistry) 60.0g NH4NO3 NH4NO3(s) N2O(g) + 2H2O(l) 3. How much water in grams is produced in this reaction? 27.0g H2O Answer in classwork section of notebook: N2 (g) + 3H2 (g) 2NH3 (g) 1. Calculate the number of grams of ammonia produced by the reaction of 5.40 g of H2 with N2. (30.6 g NH3) 2. Calculate the number of liters of N2 needed in order to react with 0.78 moles of H2. (5.8 L N2) 3. Calculate the grams of N2 needed in order to produce 9.23 x 1023 molecules of NH3. (21.5 g N2) Particle A Mass A Volume A 6.022x1023 Molar Mass 22.4 L Mole A 6.022x1023 Particle B Mole Ratio Mole Molar B Mass 22.4 L Mass B Volume B Answer in classwork section of notebook: N2 (g) + 3H2 (g) 2NH3 (g) 1. Calculate the number of grams of ammonia produced by the reaction of 5.40 g of H2 with N2. (30.6 g NH3) 2. Calculate the number of liters of N2 needed in order to react with 0.78 moles of H2. (5.82 L N2) 3. Calculate the grams of N2 needed in order to produce 9.23 x 1023 molecules of NH3. ◦ (21.5 g N2) Ch 9.2: Answer #2-4 on page 311 You will ALWAYS use the new MOLE-MOLE ratio step to get you from where you are to where you are are going. Particle A Mass A Volume A 6.022x1023 Molar Mass 22.4 L Mole A 6.022x1023 Particle B Mole Ratio Mole Molar B Mass 22.4 L Mass B Volume B Carbon dioxide is produced from the synthesis of oxygen gas with carbon monoxide. Write and balance this chemical equation and then tell how many liters of oxygen gas are required to burn 3.86 liters of carbon monoxide. Assume STP. ◦ (1.93 L O2) Aluminum reacts with oxygen to produce Aluminum Oxide. How many moles of aluminum are needed to form 3.7 moles of Aluminum Oxide? Write the balanced equation and solve. ◦ (7.4 mol Al) How many molecules of oxygen gas are produced when 29.2 g of water is decomposed? The balanced chemical equation is given for you. Use your new mole map to solve. 2H2O –electricity 2H2 + O2 ◦ (4.88 * 1023 molecules of O2) How many molecules of oxygen are produced by the decomposition of 6.54 g of Potassium Chlorate? The balanced chemical equation is given for you. Use your new mole map to solve. 2KClO3 2KCl + 3O2 ◦ (4.82 * 1022 molecules of O2) Sodium hydroxide reacts with Sulfuric acid to produce water and Sodium Sulfate. Calculate the amount of water (in grams) that would be produced from 40.87 g of the acid. ◦ (15.0 g H2O) In a combustion reaction, C2H4 reacts with oxygen to produce H2O and CO2 in the following reaction. Balance it and then determine the amount of oxygen (in grams) that is consumed if 2.69g of water is produced. ◦ _____C2H4 + _____O2 _____CO2 + _____H2O (7.17 g O2) Mole ratio: (balanced equation) Molar mas: (periodic table) Amount X Mole unknown x molar mass unknown(g) of given Mole given 1 mole unkown = (mol) Molar mas: (periodic table) Mass of X 1 mole given x given (g) molar mass = given (g) mass of unkown (g) Mole ratio: (balanced equation) mol unknown mol given Amount unkown (mol) Mass of given (g) 1 mole given mol unknown X molar mass x mol given X = given (g) mole mass 1 mol unknown mass of unknown (g) End day Carbon dioxide is produced from the synthesis of oxygen gas with carbon monoxide. Write and balance this chemical equation and then tell how many liters of oxygen gas are required to burn 3.86 liters of carbon monoxide. Assume STP. 1. ◦ (1.93 L O2) Particle A Mass A Volume A 6.022x1023 6.022x1023 Particle B Molar Mass Mole A 22.4 L Mole Ratio Mole Molar Mass Mass B B 22.4 L Volume B The difference in the optimal, expected outcome and the actual tested outcome • Experimentation is not perfect • Not all reactant are react so some may be left over • Conditions may not be perfect for a full reaction Limiting reagent: reactant that determines the amount of product that can be produced. ◦ It limited… Excess reagent: reactant that is not used up in the reaction - there is more available than needed Steps to determine LR Calculate theoretical yield (g or mol) Determine limited reagent Use the original actual yield of the limiting reactant to calculate product produced (in moles or grams) Flask 1 2 3 4 5 6 Volume acetic acid (mL) 25ml 25ml 25ml 25ml 25ml 25ml Sodium 0.50g bicarbon ate (g) 1.00g 1.50g 2.00g 2.50g 3.00g Which system will produce the most CO2 product? Ex 1. Given the following balanced equation, determine which is the LR if 2.70 moles of C2H4 is reacted with 6.30 moles of O2. C2H4 + 3O2 2H2O + 2CO2 ◦ (O2 is LR) 2.70 mol C2H4 x 2 mole H2O = 5.4 mol H2O 1 mole C2H4 6.30 mol O2 x 2 mole H2O = 4.20 mol H O 2 3 mole O2 Less= limiting reagent=O2 2. Using the info gathered from above, calculate the GRAMS of water that will be produced. 4.20mol x 18g/mol = 75.6 g H2O 3. Identify the LR when 6.00 g HCl reacts with 5.00 g Mg in the following reaction: Mg + 2HCl MgCl2 + H2 (HCl is LR) 4. Using the info gathered from above, calculate the GRAMS of hydrogen gas that will be produced. ◦ (0.164 g H2) % yield = ____actual yield___ x 100 theoretical yield measure of the efficiency of a reaction carried out in lab. Actual yield would be given in problem or determined from actually performing the lab. Theoretical yield can be calculated using the Limiting Reagent. If 15.0 g of nitrogen gas reacts with 15.0 g of hydrogen gas, 10.5 g of ammonia (NH3) is produced. Calculate the percent yield. ◦ ◦ ◦ ◦ ◦ N2 yields 1.07 mol NH2 H2 yields 5.0mol NH2 Limiting reactant: N2 (theoretical yield: 18.2 g NH3) (percent yield: 57.7%) 1. Balance chemical equation 2. Find limiting reactant 3. Calculate theoretical yield 4. Find percent yield % yield = ____actual yield___ x 100 theoretical yield Calculate the number of moles in 9.023 x 1023 molecules of NO2. (6.48 moles) Calculate the volume of 2.30 moles of SO2 gas at STP. (51.5 L) Find the molar mass of B2(SO3)3. 261.9 g/mol HS-PS1-7. Use mathematical representations to support the claim that atoms, and therefore mass, are conserved during a chemical reaction. HS-PS1-6. Refine the design of a chemical system by specifying a change in conditions that would produce increased amounts of products at equilibrium. HS-PS1-5. Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs. HS-PS1-3. Plan and conduct an investigation to gather evidence to compare the structure of substances at the bulk scale to infer the strength of electrical forces between particles. HS-PS1-7. Use mathematical representations to support the claim that atoms, and therefore mass, are conserved during a chemical reaction. CA State Standards D2. Investigate quantitative relationships in chemical reactions, and solve related problems; D3. Demonstrate an understanding of the mole concept and its significance to the quantitative analysis of chemical reactions. HS-PS1-6. Refine the design of a chemical system by specifying a change in conditions that would produce increased amounts of products at equilibrium. HS-PS1-5. Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs. HS-PS1-3. Plan and conduct an investigation to gather evidence to compare the structure of substances at the bulk scale to infer the strength of electrical forces between particles.