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Unit 9: Stoichiometry Define this word?
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Bellringer: S’Mores How many S’mores could you make with the ingredient below? Explain your reasoning and how you calculated your answer (must be at least three sentence)
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Real Life Application We cannot forget about the law of conservation of mass. The mass of what we put in must be equal to what we get out. Key Concept 1: The excess reactants are all the leftover unused reactants. (The reactant that’s leftover).
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Real Life Application Since we have conservation of mass we also need to take into consideration that limits reactions. Key Concept 2: The limiting reactant limits the extent of the reaction and, thereby, determines the amount of product formed. (The reactant that's all used up).
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Real Life Application What wrong with having excess?
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“a political system in which a country’s trade and industry are controlled by private owners for profit” What is Capitalism?
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Push you desk in to shoulder partners: Briefly discuss both of these questions and be prepared to share. – If companies want to make a profit, what do they want to avoid? – If they don’t pay attention to waste, what are the outcomes? Why is this Relevant?
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What are they? – Prepare specific medications for individualized patients. – Medication’s ingredients are mixed together in the exact strength and dosage required by the individual patient. – Good for patients with allergies. Compounding Pharmacies
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Not your typical Pharmacy!
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With your shoulder partner, discuss why you think that compounding pharmacy is an excellent example of a profession that has to be mindful of limiting and excess reagents. – Why is is important that they pay attention excess and limiting reagents? How do you think this relates?
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Compounding Pharmacist Mortar and Pestle Compounding Pharmacy At the END OF UNIT 9 you will be able to compound 2 grams of calcium carbonate, the active ingredient in Tums for the Mortar and Pestle Compounding Pharmacy using stoichiometry and good lab techniques.
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Compounding Pharmacist CaCl 2 (aq) + 2KCO 3 (aq) Ca(CO 3 ) 2 (s) + 2KCl (aq) You want to make 2 grams of Ca(CO 3 ) 2 how much reactants would you have to mix?
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Closure- Exit Pass 2Al(s) + 3CuCl 2 (aq) → 3Cu(s) + 2AlCl 3 (aq) 1.Define excess vs. limiting reagent. 2.If you were an chemical engineer manufacturing aluminum chloride, what would you want to be your excess reagent (Al is less expensive than CuCl 2 ) and why?
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Particle and Mole Relationships Chemical reactions stop when one of the reactants is used up. Key Concept 3: Stoichiometry is the study of quantitative relationships between the amounts of reactants used and amounts of products formed by a chemical reaction. (It’s the math that figures out how to not have excess)Stoichiometry So based on how much reactant you put in you can calculate how much product you will get out.
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Particle and Mole Relationships (cont.) Key Concept: 4
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Particle and Mole Relationships (cont.) Key Concept 5: A mole ratio is a ratio between the numbers of moles of any two substances in a balanced equation.mole ratio This can only be determined from a balanced chemical equation. Let practice: What is the mole-to-mole ratio for…… a.10C 2 H 4 O + 15O 2 20CO 2 + 2H 2 O b.CH 4 + 2O 2 CO 2 + 2H 2 O c.H 2 + O 2 H 2 O
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Hide Conversion Factors The quantities of a conversion factor have to be equal. = Sign The word per The word for The word in Ratio
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New Conversion Factor Mole to Mole Ratio What are the other two conversion factors you already know that are related to moles?
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Avogadro's Principle Key Concept 6: Avogadro’s principle Key Concept 6: Avogadro’s principle states that equal volumes of gases at the same temperature and pressure contain equal numbers of particles.
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Particle and Mole Relationships (cont.) Key Concept: 4
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Stoichiometry and Volume-Volume Problems Coefficients in a balanced equation represent volume ratios for gases.
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Avogadro's Principle (cont.) Key Concept 7: The molar volume of a gas is the volume 1 mol occupies at 0.00°C and 1.00 atm of pressure.molar volume REVIEW: What is STP? Key Concept 8: At STP, 1 mol of gas occupies 22.4 L. NEW CONVERSION FACTOR (LAST ONE)
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Let’s make a Tool Box
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Converting Units (cont) Factor Labeling Step 1.Determine what the question is asking you to solve for. 2.Determine what is given in the problem to be converted. 3.Identify and plug in the appropriate conversion factors as fractions (what is on top must also be on bottom). 4.Cancel units 5.Verify your answer. (Units must match units in step 1. If the answer doesn’t match, repeat 3 and 5).
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Key Concept 9: How many moles are in 15 liters of Oxygen gas at STP? Practice Makes Perfect
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Key Concept 10: If I have 2.5 moles of Ca(OH) 2 how many grams do I have? Practice Makes Perfect
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Key Concept 11: If I have 2 liters of water vapor (H 2 0) how many grams do I have? Practice Makes Perfect
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Using Stoichiometry Key Concept 12: All stoichiometric calculations begins with a balanced chemical equation. 4Fe(s) + 3O 2 (g) 2Fe 2 O 3 (s)
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Using Stoichiometry 4Fe(s) + 3O 2 (g) 2Fe 2 O 3 (s) Key Concept 13: Grams--- Mole---Mole--- Grams How many grams of iron are required to react with 15.0 g oxygen gas in the following reaction? How many grams of iron (III) oxide are produced is 15.0 g oxygen gas reaction in excess iron?
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Using Stoichiometry 4Fe(s) + 3O 2 (g) 2Fe 2 O 3 (s) Key Concept 14: How many grams of iron (III) oxide are produced is 25 grams of oxygen react with 30 grams of iron, what is the limiting factor?
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Stoichiometry of Reactions Involving Gases The gas laws can be applied to calculate the stoichiometry of reactions in which gases are reactants or products. 2H 2 (g) + O 2 (g) → 2H 2 O(g) Key Concept 15: How many liters of water vapor are produced when 3.5 liter of oxygen and excess hydrogen gas react?
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Using Stoichiometry (cont.) Key Concept 16: How many grams of lithium nitrate will be needed to make 250 grams of lithium sulfate, assuming that you have an adequate amount of lead (IV) sulfate to do the reaction? __Pb(SO 4 ) 2 + __LiNO 3 __Pb(NO 3 ) 4 + __Li 2 SO 4
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Using Stoichiometry (cont.)
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Calculating the Product when a Reactant is Limiting Key Concept 16: 2Cu(s) + S(s) → Cu 2 S(s) 80.0g Cu reacts with 25.0g S A.Determine which is the limiting reactant. B.Calculate how much Cu 2 S if formed?
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Socrative What volume will 18 moles of C 4 H 4 gas take up at STP? A.22.4 liters B.403 liters C.0.8 liters D.None of the above
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Socrative How many mol of hydrogen gas are required to react with 1.50 mol oxygen gas in the following reaction? 2H 2 (g) + O 2 (g) → 2H 2 O(g) A.0.75 B.3 C.36 D.None of the above
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A.A B.B C.C D.D Socrative How many liters of hydrogen gas are required to react with 3.25 liters of oxygen gas in the following reaction? 2H 2 (g) + O 2 (g) → 2H 2 O(g) A.2.00 B.3.25 C.4.00 D.6.50
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Compounding Pharmacist Mortar and Pestle Compounding Pharmacy Situation: I told Mrs. Driebe and Mrs. Lieb that you could: Predict the products in a double replacement reaction Balance the equation Practicing stoichiometry. Goal: Is to compound 2 grams of calcium carbonate, the active ingredient in Tums for the Mortar and Pestle Compounding Pharmacy using stoichiometry and good lab techniques.
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Compounding Pharmacist CaCl 2 (aq) + 2KCO 3 (aq) Ca(CO 3 ) 2 (s) + 2KCl (aq) You want to make 2 grams of Ca(CO 3 ) 2 how much reactants would you have to mix? How does Ca(CO 3 ) 2 work in the stomach? How do antacids relieve heartburn?
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Closure: Exit Pass On average a Pharmacists makes $50 an hour in Arizona. Today you did one job a Pharmacist is trained to do. Could you see yourself as a Pharmacist? Why or why not.
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