CO(g) + O2(g) CO2(g) 2 mol 1 mol 2 mol 44.8 L 22.4 L 44.8 L 1.204(10) 24 molecules 6.02(10) 23 molecules 1.204(10) 24 molecules g 32.0 g 88.

Transcription

1 Chapter 12 STOICHIOMETRY CO(g) + O2(g) CO2(g) 2 mol 1 mol 2 mol 44.8 L 22.4 L 44.8 L 1.204(10) 24 molecules 6.02(10) 23 molecules 1.204(10) 24 molecules 56.0 g 32.0 g 88.0 g Moles, Liters, and Particles follow coefficient RATIOS Grams DO NOT follow same coefficient ratios only Law of Conservation of Mass Ex. 2(28.0 g) (32.0 g) 2(44.0 g) 88.0 g 88.0 g CHEMISTRY Chapter 12 Scotch Plains-Fanwood High School Page 1

2 Practice...[on the equation below (first BALANCE it!)] CO(g) + O2(g) CO2(g) a. mol 3.0 mol mol b. 4.0 mol mol mol c. L L 12.0 L d. 5.0(10) 20 molecules molecules molecules e. L 7.0 L L f. molecules molecules molecules g. 112 g g g h. g 48 g g i. g g 22 g CHEMISTRY Chapter 12 Scotch Plains-Fanwood High School Page 2

3 more practice (remember to balance ) N2 + H2 NH3 a mol mol mol b. mol mol 6.2 mol c. L 12.0 L L d. molecules molecules 2.40(10) 23 molecules e. g 6.0 g g f g g g g. g g 50.0 g h g g g CHEMISTRY Chapter 12 Scotch Plains-Fanwood High School Page 3

4 Limiting Reagents Often in chemistry, the amount of product is limited because one reagent [reactant] runs out before the other. Ex: Find the limiting reagent in each of the following: H2 + O2 H2O initial 4.0 mol 4.0 mol 0 mol change final limiting reagent was N2 + H2 NH3 initial 3.0 mol. 6.0 mol. 0 mol. change final limiting reagent was NH3 + O2 N2 + H2O initial 16.0 L 12.0 L 0 L 0 L change final limiting reagent was H2 + O2 H2O initial 12.0 g 16.0 g 0 g change final limiting reagent was CHEMISTRY Chapter 12 Scotch Plains-Fanwood High School Page 4

5 Percent Yield C(s) + H2(g) CH4(g) Ex. Suppose that 18.0 g C(s) makes 20.0 g CH4(g) in an experiment with unlimited H2(g). Find the % Yield g g C(s) + Cl2(g) CCl4(g) a. Ex. Suppose that 49.7 g of Cl2(g) makes 42.1 g CCl4(g) in an experiment with unlimited C(s). Find the % Yield g g b. Ex. Suppose that the reaction above is 70.0% efficient. How much CCl4(g) would you get if you had started with 60.0 g C with unlimited Cl2(g)? CHEMISTRY Chapter 12 Scotch Plains-Fanwood High School Page 5

6 Stoichiometry Partners worksheet Directions: Balance the following equation and fill in the correct stoichiometric relationships. C6H6(g) + O2(g) CO2(g) + H2O(g) g g g g 2. L L 30.0 L L 3. molecules molecules molecules 2.0(10) 20 molecules 4. mol 3.75 mol mol mol 5. g g 11.0 g g 6. g g g 3.0g 7. molecules molecules 9.3(10) 18 molecules molecules To answer the word problems below, you can use a similar procedure as you did in #1-7 above. Read each question below and then set up your own blanks at the bottom of the page to fill in the information given and then solve for the unknown values. Remember to follow the appropriate ratios for mol, L, particles, vs. grams. 8. a. How many Liters of CO2(g) can be formed from 14.0 L C6H6(g)? b. How many Liters of O2(g) are needed to react with 14.0 L C6H6(g)? 9. a. How many molecules of C6H6(g) must react with 4.5(10) 23 molecules of O2(g)? b. How many molecules of H2O(g) could be made from 4.5(10) 23 molecules of O2(g)? 10. a. How many grams of C6H6(g) are required to form 66.0 g of CO2(g)? b. How many grams of H2O(g) would be formed at the same time? 11. a. How many moles of H2O(g) could you form from 7.50 mol of O2(g)? b. How many moles of C6H6(g) would you need to do this? C6H6(g) + O2(g) CO2(g) + H2O(g) 8. L L L L 9. molecules molecules molecules molecules 10. g g g g 11. mol mol mol mol CHEMISTRY Chapter 12 Scotch Plains-Fanwood High School Page 6

7 Stoichiometry Practice worksheet 1 Directions: Answer each of the exercises below. 1. Balance the following equation and fill in the correct stoichiometric relationships in the blanks. C4H10(g) + O2(g) CO2(g) + H2O(g) a. mol 2.60 mol mol mol b. L L 32.0 L L c. molecules molecules 1.6(10) 23 molecules molecules The questions below can be calculated the in the same way as the above questions. Use the numbered spaces at the bottom of the page to figure out and fill in answers. 2. a. How many Liters of CO2 can be formed from 36.0 L C4H10(g)? b. How many LIters of O2 are needed to react with 36.0 L C4H10(g)? 3. a. How many moles of C4H10 (g) are required to react with 6.50 mol of O2(g)? b. How many moles of H2O (g) would be formed from 6.50 mol of O2(g)? 4. a. How many molecules of CO2(g) could be made from 4.0(10) 23 molecules of C4H10(g)? b. How many molecules of O2(g)would be needed to react with 4.0(10) 23 molecules of C4H10(g)? C4H10(g) + O2(g) CO2(g) + H2O(g) 2. a. b. L L L L 3.a.b. mol mol mol mol 4.a.b. molecules molecules molecules molecules CHEMISTRY Chapter 12 Scotch Plains-Fanwood High School Page 7

8 Stoichiometry Practice worksheet 2 Directions: Answer each of the exercises below. Balance the following equation and fill in the correct stoichiometric relationships. C2H4(g) + O2(g) CO2(g) + H2O(g) 1. mol 4.50 mol mol mol 2. L L 24.0 L L g g g g 4. g 57.6 g g g To answer the word problems below, you can use a similar procedure as you did in #1-4 above. Read each question below and then use the blanks at the bottom of the page to fill in the information given and then solve for the unknown values. Remember to follow the appropriate ratios for mol, L, particles, vs. grams. 5. a. How many Liters of CO2(g) can be formed from 33.6 L C2H4(g)? b. How many Liters of H2O(g) can be formed from 33.6 L C2H4(g)? c. How many Liters of O2(g) are needed to react with 33.6 L C2H4(g)? 6. a. How many molecules of CO2(g) could be made from 4.0(10) 23 molecules of C2H4(g)? b. How many molecules of H2O(g) could be made from 4.0(10) 23 molecules of C2H4(g)? c. How many molecules of O2(g) need to react with 4.0(10) 23 molecules of C2H4(g)? 7. a. How many grams of C2H4 (g) are required to react with 2.40 g of O2(g)? b. How many grams of H2O (g) would be formed from 2.40 g of O2(g)? c. How many grams of CO2 (g) would be formed from 2.40 g of O2(g)? C2H4(g) + O2(g) CO2(g) + H2O(g) 5. a. b. c. L L L L 6.a. b. c. molecules molecules molecules molecules 7.a. b. c. g g g g CHEMISTRY Chapter 12 Scotch Plains-Fanwood High School Page 8

9 Stoichiometry Practice worksheet 3 Directions: Balance the following equations and fill in the correct stoichiometric relation. N2(g) + H2(g) NH3(g) 1. mol mol 0.12 mol (10) 23 molecules molecules molecules 3. g 36.0 g g 4. L L 39.0 L To answer the word problems below, you can use a similar procedure to the one you did in #1-4 above. Read each question below and then use the blanks at the bottom of the page to fill in the information given and then solve for the unknown values. Remember to follow the appropriate ratios for mol, L, particles, vs. grams. 5. a. How many moles of H2(g) are required to react with 4.8 mol of N2(g)? b. How many moles of NH3(g) would be formed from 4.8 mol of N2(g)? 6. How many Liters of each reactant would be required to form 72.0 L of NH3(g) if all reactants and products were gases at STP? 7. a. How many moles of N2(g) are required to combine with 6.4 mol of H2(g)? b. How many moles of NH3(g) would be formed from 6.4 mol of H2(g)? 8. a. How many grams of N2(g) are required to react with 18.0 g of H2(g)? b. How many grams of NH3(g) would be formed from 18.0 g of H2(g)? 9. a. How many grams of N2(g) are required to form 85.0 g of NH3(g)? b. How many grams of H2(g) are required to form 85.0 g of NH3(g)? N2(g) + H2(g) NH3(g) 5. mol mol mol 6. L L L 7 a. b. mol mol mol 8 a. b. g g g 9 a. b. g g g CHEMISTRY Chapter 12 Scotch Plains-Fanwood High School Page 9

10 Limiting Reagents worksheet #1 Directions: Answer each of the exercises below. 1. Balance the following equation and answer the following questions. C3H8(g) + O2(g) CO2(g) + H2O(g) initial change final a. You are given 3.0 mol. of C3H8, 10.0 mol. of O2, and no products to begin with. Fill in these values in the appropriate places above. b. If you use up all of the 3.0 mol. of C3H8 above, how much O2 would you need? [compare with the ratios of your balanced equation] c. If you use up all of the 10.0 mol. of O2 above, how much C3H8 would you need? [compare with the ratios of your balanced equation] Decide which reagent will run out first and fill in the change line following the ratios your balanced equation. d. Fill in the final line e. How many moles of C3H8 will be left over? f. How many moles of O2 will be left over? g. How many moles of CO2 will be formed? h. How many moles of H2O will be formed? i. What was the limiting reagent in this reaction? CHEMISTRY Chapter 12 Scotch Plains-Fanwood High School Page 10

11 Limiting Reagents worksheet #2 Directions: Answer each of the exercises below. 1. Balance the following equation and answer the following questions. Mg(s) + AlCl3(aq) MgCl2(aq) + Al(s) Initial change final a. You are given 6.0 mol of Mg, 6.0 mol of AlCl3, and no products to begin with. Fill in these values in the appropriate places above. b. If you use up all of the 6.0 mol. of Mg above, how much AlCl3 would you need? [compare with the ratios of your balanced equation] c. If you use up all of the 6.0 mol. of AlCl3 above, how much Mg would you need? [compare with the ratios of your balanced equation] Decide which reagent will run out first and fill in the change line following the ratios your balanced equation. d. Fill in the final line e. How many moles of Mg will be left over? f. How many moles of AlCl3 will be left over? g. How many moles of MgCl2 will be formed? h. How many moles of Al will be formed? i. What was the limiting reagent in this reaction? CHEMISTRY Chapter 12 Scotch Plains-Fanwood High School Page 11

12 Limiting Reagents worksheet #3 Directions: Answer each of the exercises below. Fill in each table after finding the limiting reagent in each after proper BALANCING!! 1. NO(g) + O2(g) NO2(g) initial 5.6 mol 5.6 mol 0 mol change final 2. NO(g) + O2(g) NO2(g) initial 14.0 L 6.0 L 0 L change final 3. NO(g) + O2(g) NO2(g) initial 15.0 g 64.0 g 0 g change final Now answer the following questions using the above information and appropriate conversions In #1 above... a. how many moles of product were formed? b. how many liters of which reactant were left over? c. how many grams of NO2(g) were formed? In #2 above... a. how many liters of NO(g) were USED? b. what was the limiting reagent? c. how many grams of NO2(g) were In #3 above... a. how many grams of reactant were left over? b. how many grams of product were formed? c. how many liters of NO2(g) were CHEMISTRY Chapter 12 Scotch Plains-Fanwood High School Page 12

13 Lab Write-Up Lab12 Baking Soda Stoichiometry (Rough Copy) Name Date Period Partner(s) Directions: Fill in the appropriate information below based on your data. DATA: mass of crucible and cover (Before heating) mass of crucible and cover + NaHCO3(s) (After heating) mass of crucible and cover + Na2CO3(s) CALCULATIONS: SHOW your WORK; BOX in answers; include UNITS. 1. Find the mass of the baking soda (NaHCO3) before heating. 2. Find the mass of the sodium carbonate (Na2CO3) after heating (experimental). 3. Find the mass of just the sodium carbonate (Na2CO3) you SHOULD have formed (theoretical) from the amount of baking soda (NaHCO3) with which you started. Balance equation! NaHCO3(s) Na2CO3(s) + CO2(g) + H2O(g) g g 4. Find the % Yield of sodium carbonate (Na2CO3). %Yield = experimental x 100% theoretical CHEMISTRY Chapter 12 Scotch Plains-Fanwood High School Page 13

14 Lab-Stoichiometry and Percent Yield of Baking Soda Write -Up Name Date Period YOUR LAB REPORT MUST BE TYPED IN ALL PARTS! Heading Include your name, partner s name, teacher, date due, period, Title Purpose Include this heading in your lab report One sentence (include the name of the reactant and product that you will be measuring masses of) Introduction Include this heading in your lab report Show balanced equation Explain the stoichiometry calculation (bridge) of the reaction Explain % Yield and how it relates to this lab Materials Include this heading in your lab report In a LIST format (not a paragraph) Procedure Include this heading in your lab report LIST step by step Don t need to be complete sentences Data Include this heading in your lab report 3 pieces of data include label, measurement, and unit for each as outlined on handout Lab-Write-up Lab12 Baking Soda Stoichiometry Example: length of pencil = cm Calculations Include this heading in your lab report Show calculations as outlined on handout Lab-Write-up Lab12 Baking Soda Stoichiometry INCLUDE THE QUESTIONS as on the handout Conclusion Include this heading in your lab report This paragraph pulls your whole lab together. You will be stating things in the conclusion that you have already shown in the lab report. Restate purpose Include the balanced equation again State your initial amount of baking soda State your experimental amount of sodium carbonate State your theoretical (stoichiometric) amount of sodium carbonate you should have made State your percent yield State a reason that your % Yield was higher than 100% or why it was lower than 100% CHEMISTRY Chapter 12 Scotch Plains-Fanwood High School Page 14

15 The following lab report has some room for improvement correct it Pete Moss Date Due: March 15, 2015 Partner: Sandy Beach Period: 3.4 Teacher: My First Lab Report Purpose The purpose of this lab was to find the % Yield Introduction NAHCO3(s) Na2Co3(s) + H2O(l) + CO2(g) We calculated how much sodium carbonate we were supposed to make and found the percent yield. Materials Ring stand, ring clamp, Bunsen burner, flint striker, baking soda, balance, crucible Procedure 1) goggles 2) set up ring stand and equipment 3) heat baking soda in crucible for 7-8 minutes uncovered 4) cool 5) mass crucible, cover, and sodium carbonate 6) clean up Data mass of crucible and cover = g (before heating)mass of crucible, cover, NaHCO3 = g (after heating) mass of crucible, cover, Na2CO3 = g Calculations 1. Find the mass of the baking soda (NaHCO3) before heating g g = 3.10 g NaHCO3 2. Find the mass of sodium carbonate (Na2CO3) after heating (experimental) g g = 1.91 g Na2CO3 CHEMISTRY Chapter 12 Scotch Plains-Fanwood High School Page 15

16 3. Find the mass of just the sodium carbonate (Na2CO3 ) you SHOULD have formed (theoretical) from the amount of baking soda (NaHCO3 ) with which you started. Balance the equation! NAHCO3(s) Na2Co3(s) + H2O(l) + CO2(g) 3.10 g 1.96 g 3.10 / 84 * 106 = 1.96 g Na2CO3 4. Find the % Yield of sodium carbonate (Na2CO3) % Yield = experimental * 100% theoretical 103 % Yield = 1.96 * 100% 1.91 Conclusion In this lab we were trying to find the % Yield of sodium carbonate (Na2CO3) from baking soda (NaHCO3) according to the balanced equation below: NAHCO3(s) Na2Co3(s) + H2O(l) + CO2(g) We started off with 3.10 g of baking soda and obtained 1.91 g of sodium carbonate, but we should have obtained 1.96 g of sodium carbonate. We had a 103% yield as a result. We had a percent yield that was too high (higher than 100%) because we probably didn t heat up our sample long enough. CHEMISTRY Chapter 12 Scotch Plains-Fanwood High School Page 16