* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Starter S-30
Marcus theory wikipedia , lookup
Artificial photosynthesis wikipedia , lookup
Computational chemistry wikipedia , lookup
Biochemistry wikipedia , lookup
Isotopic labeling wikipedia , lookup
Enantioselective synthesis wikipedia , lookup
Hypervalent molecule wikipedia , lookup
Gas chromatography–mass spectrometry wikipedia , lookup
Chemical industry wikipedia , lookup
Catalytic reforming wikipedia , lookup
Photoredox catalysis wikipedia , lookup
Determination of equilibrium constants wikipedia , lookup
Water splitting wikipedia , lookup
Multi-state modeling of biomolecules wikipedia , lookup
Supramolecular catalysis wikipedia , lookup
Chemical equilibrium wikipedia , lookup
Electrochemistry wikipedia , lookup
Atomic theory wikipedia , lookup
Asymmetric induction wikipedia , lookup
Electrolysis of water wikipedia , lookup
Organosulfur compounds wikipedia , lookup
Photosynthetic reaction centre wikipedia , lookup
Physical organic chemistry wikipedia , lookup
Stille reaction wikipedia , lookup
Rate equation wikipedia , lookup
George S. Hammond wikipedia , lookup
Strychnine total synthesis wikipedia , lookup
Metalloprotein wikipedia , lookup
Hydrogen-bond catalysis wikipedia , lookup
Ring-closing metathesis wikipedia , lookup
Transition state theory wikipedia , lookup
Chemical thermodynamics wikipedia , lookup
Chemical reaction wikipedia , lookup
Bioorthogonal chemistry wikipedia , lookup
Lewis acid catalysis wikipedia , lookup
Petasis reaction wikipedia , lookup
Discodermolide wikipedia , lookup
Click chemistry wikipedia , lookup
Starter S-125 1.2 moles NaC2H3O2 are used in a reaction. How many grams is that? Chapter 12 Stoichiometry Chapter 12 12.1 The Arithmetic of Equations 12.1 The Arithmetic of Equations The basis for solving stoichiometry problems is a balanced chemical reaction NN2 (2g()g 3H 2 ( g ) 2NH NH3(3g()g ) ) A balanced reaction is used to calculate How much reactant is needed How much product is produced 12.1 The Arithmetic of Equations Stoichiometry – the calculation of quantities N 2 ( g ) 3H 2 ( g ) 2 NH 3( g ) This reaction produces Ammonia which is used in fertilizers Balanced reactions are usually used to calculate grams of product or reactant 12.1 The Arithmetic of Equations Analysis of the reaction N 2 ( g ) 3H 2 ( g ) 2 NH 3( g ) Atoms – 2 atoms of nitrogen combine with 6 atoms of hydrogen – product is 2 nitrogen and 6 hydrogen Molecules – 1 molecule of nitrogen gas combines with 3 molecules of hydrogen gas to produce 2 molecules of ammonia 12.1 The Arithmetic of Equations Analysis of the reaction N 2 ( g ) 3H 2 ( g ) 2 NH 3( g ) Most useful Moles – 1 mole of nitrogen gas reacts with 3 moles of hydrogen gas to produce 2 moles of ammonia 12.1 The Arithmetic of Equations Analysis of the reaction N 2 ( g ) 3H 2 ( g ) 2 NH 3( g ) Mass is always conserved in a chemical reaction 12.1 The Arithmetic of Equations Analysis of the reaction N 2 ( g ) 3H 2 ( g ) 2 NH 3( g ) The key moles can be converted to grams grams can be converted to moles Volume – remember that one mole of gas at STP is 22.4L 12.1 The Arithmetic of Equations Analysis of the reaction N 2 ( g ) 3H 2 ( g ) 2 NH 3( g ) The key moles can be converted to grams grams can be converted to moles Volume – remember that one mole of gas at STP is 22.4L 12.1 The Arithmetic of Equations Analysis of the reaction N 2 ( g ) 3H 2 ( g ) 2 NH 3( g ) So if we start with 50g of N2, how many moles do we have 2molNH 1mol 3 2 1.38.mol 502gN 1.8molN 6molNH3 28 g2 1molN How many moles of NH3 would be produced? For every 1 mole of N2, 2 moles of NH3 12.1 The Arithmetic of Equations Analysis of the reaction N 2 ( g ) 3H 2 ( g ) 2 NH 3( g ) How many grams of ammonia are produced 2molNH 17 gNH 3 3 3.661 13.8.6molN molNH molNH gNH 33 2 3 1molNH 2 3 1molN Starter S-126 A. Balance the following reactions H2SO4 + KOH K2SO4 + H2O B. What is the molar mass of the sulfuric acid. C. If 20.0g of sulfuric acid is used, how many moles is that? D. How many moles of water would be produced? Chapter 12 12.2 Chemical Calculations 12.2 Chemical Chemical Calculations Calculations 12.2 Mole Ratios Come from balanced chemical reactions 2HH 3O 2SO 2H O 2S 2 S O22 SO2 2 H 2O2 Conversion factors derived from the coefficients in the balanced reactions 2molSO2 2molH 2O 3molO2 3molO2 2molH 2 S 2molH 2 S 12.2 Chemical Calculations Mole-Mole Calculations 2H 2 S 3O2 2SO2 2H 2O It is possible to convert from one quantity in a balanced reaction to another using mole ratios For example – if 3.7 moles of sulfur dioxide is produced, how many moles of oxygen were used? 3molO2 3.7molSO2 5.6molO2 2molSO2 12.2 Chemical Calculations Mass-Mass Calculations 2H 2 S 3O2 2SO2 2H 2O Three steps 1. Convert given mass values into mole values. 2. Use a mole ratio to convert to the moles that the question requests 3. Convert this mole quantity to a mass value 12.2 Chemical Calculations Mass-Mass Calculations 2H 2 S 3O2 2SO2 2H 2O How many grams of Oxygen are needed to produce 30.0g of Sulfur Dioxide? 1molSO 31.9988 3molO 2 2gO2 0.468 30.0 0.702 gSO molSO molO 22.5 molSO molO gO222 0.468 0.702 2 22 1gSO molO 64.06 2molSO 2 22 12.2 Chemical Calculations Volume-Mass Calculations 2 NO( g ) O2(2(gg)) 2NO NO2(2(g )g ) Same steps, but volume is converted to moles, or moles to volume Example: If 4.0L of nitrogen monoxide reacts, how many grams of oxygen are used? 131.9998 molO2 gO2 1molNO 0.090 molO 29 gO2 2 4.0molNO LNO 0.18 0.090 molO molNO 2 1molO 0.18 LNO 2 22.4 2molNO Starter S-127 A. Balance the following reactions Al(NO3)3 + Na2SO4 Al2(SO4)3+NaNO3 B. If 50.0g of Aluminum Nitrate reacts, how many grams of Aluminum Sulfate are produced? Chapter 12 12.3 Limiting Reagent and Percent Yield 12.3 Limiting Reagent and Percent Yield Limiting Reagent – the reactant that runs out first 2Cu CuSS Cu Cu22SS Amounts of both reactants are given Example: 80.0g Copper, 25.0g Sulfur 1. Calculate how many moles would each reactant produce Copper 1molCu 1molCu S 2 .0 gCu .26molCu 2 S 1.2680 molCu 01.630 .55 gCu molCu 263 12.3 Limiting Reagent and Percent Yield Limiting Reagent – the reactant that runs out first 2Cu CuSS Cu Cu22SS Amounts of both reactants are given Example: 80.0g Copper, 25.0g Sulfur 1. Calculate how many moles would each reactant produce Sulfur 1molS2 S 1molCu 0.780molS .0 gS 0.78025 molS molCu2 S .06 gS 1molS 32 12.3 Limiting Reagent and Percent Yield Limiting Reagent – the reactant that runs out first 2Cu CuSS Cu Cu22SS From the reactions Copper would produce 0.630 mol Cu2S Sulfur would produce 0.780 mol Cu2S That means copper will run out first – it is the limiting reagent Sulfur would be the excess reagent 12.3 Limiting Reagent and Percent Yield One for you now CC 3O22 2CO CO 22H O2O 2H 2H 4 4 2 2H 1. Balance the reaction 2. If 75.6g C2H4 reacts with 100.8g O2 – what is the limiting reagent? C2 H 4 5.40molH 2O O2 2.10molH 2O Oxygen 12 molC 12 molO molH 18 molH .02 O 2H 22gH 24O2O 2 2moles O of water 2How .70 .32100 6.15 gC 10 molC .molO molH 82 H gO 32are .15 2.5 10 ..70 40 molO 37 molH molC molH .8 gH O4 24 H 24 2 22O 2H 3. 75 many produced? .molC 00 molO 1gC molH gO22H 2H424O 28 32 .1 305 2.10 mol H2O 4. How many grams of water are produced? Starter S-132 A. Balance the following reactions SiO2 + C SiC + CO B. 35 grams of silicon dioxide reacts with 10.0g of Carbon, how much carbon monoxide is formed? 12.3 Limiting Reagent and Percent Yield Reactions rarely produce as much product as is predicted -reactants can be impure -reactions may not go to completion -may compete with smaller “side” reactions In some reactions as little as 60% yield is considered a good result 12.3 Limiting Reagent and Percent Yield Yield – how much product is produced Theoretical Yield – the value calculated using stoichiometry Actual Yield – the amount of product that actually forms 12.3 Limiting Reagent and Percent Yield Percent Yield – a ratio of actual to theoretical yield ActualYield PercentYield TheoreticalYield x100% This number must be 100% or less In lab the actual yield is the result you get On a test, it will be a number that is given to you The theoretical yield is calculated using limiting reactants 12.3 Limiting Reagent and Percent Yield Example: What is the theoretical yield of Calcium Oxide if 24.8g of Calcium Carbonate decomposes in the following reaction. CaCO3 CaO CO2 Balanced 56.1 gCaO 1molCaCO 1 molCaO 3 0.248 molCaO gCaO 24.8 0.248 gCaCO molCaCO 13.9 0.248 molCaCO molCaO3 0.248 3 3 1 molCaO gCaCO 3 3 100.1 1molCaCO 12.3 Limiting Reagent and Percent Yield Example: What is the percent yield if actual yield is 9.6g? 9.6 gCaO ActualYield PercentYield PercentYield PercentYield 69% x100% x100% TheoreticalYield 13.9 gCaO 56.1gCaO 0.248molCaO 13.9 gCaO 1molCaO 12.3 Limiting Reagent and Percent Yield Example: What is the theoretical yield if 15.0g of nitrogen reacts with 15.0g of hydrogen in the following reaction? NN 3H 2 2NH NH 2 2 33 Balance N 2 1.07molNH 3 H 2 4.96molNH 3 11217.031 2 molNH molH molN molNH 3 22gNH 3 3 0.536 15.0 15.0 gH molN gN22232 0.536 1.07 moldH molN molNH 1.07 7.44 molNH molH 4.96 18.2 molNH gNH 7.44 2 333 molN gH gN2222 3 molH molNH 2.016 311 28.01 12.3 Limiting Reagent and Percent Yield Example: If the actual yield is 10.5g of NH3 what is the percent yield? 10.5 gNH 3 ActualYield PercentYield x100% 57.7% x100% TheoreticalYield 3 18.2 gNH 17.031gNH 3 1.07molNH 3 18.2 gNH 3 1molNH 3