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Chemistry Week 26

Chemistry Week 26. Please get out your calculator!. March 12, 2013. AGENDA: 1 – Agenda/ Bell Ringer 2 – Pre-Lab Instructions 3 – Lab 4 – Clean-up and Post-Lab. Today’s Goal:

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Chemistry Week 26

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  1. Chemistry Week 26 Please get out your calculator!

  2. March 12, 2013 AGENDA: 1 – Agenda/ Bell Ringer 2 – Pre-Lab Instructions 3 – Lab 4 – Clean-up and Post-Lab Today’s Goal: Students will be able to determine a limiting reactant and calculate a percent yield for a laboratory experiment. Homework • Limiting Reactant Lab – Calculations due tomorrow • Stoichiometry and Limiting Reactant • If you missed Friday’s Quiz you must come make it up by Friday.

  3. Tuesday, March 12th Objective: Students will be able to determine a limiting reactant and calculate a percent yield for a laboratory experiment. Bell Ringer: Predict the products of the following chemical equation and balance (see Pre-lab): ___HCl + ___Zn  ______ + ______ (*hint: Zn is a +2 charge)

  4. 30 seconds Remaining…

  5. Tuesday, March 12th Objective: Students will be able to determine a limiting reactant and calculate a percent yield for a laboratory experiment. Bell Ringer: Predict the products of the following chemical equation and balance (see Pre-lab): ___HCl + ___Zn  ______ + ______ (*hint: Zn is a +2 charge)

  6. March 12, 2013 AGENDA: 1 – Agenda/ Bell Ringer 2 – Pre-Lab Instructions 3 – Lab 4 – Clean-up and Post-Lab Today’s Goal: Students will be able to determine a limiting reactant and calculate a percent yield for a laboratory experiment. Homework • Limiting Reactant Lab – Calculations due tomorrow • Stoichiometry and Limiting Reactant • If you missed Friday’s Quiz you must come make it up by Friday.

  7. Tuesday, March 12th Objective: Students will be able to determine a limiting reactant and calculate a percent yield for a laboratory experiment. Bell Ringer: Predict the products of the following chemical equation and balance (see Pre-lab): ___HCl + ___Zn  ___ ZnCl2+ ___ H2 (*hint: Zn is a +2 charge)

  8. Lab Notes • We completed the Pre-Lab as the Bell Ringer. Please make sure you complete it while you are doing your lab. • You need to work quickly! Let each reaction occur for at least 7 minutes, or until all bubbles stop forming. • Make sure once you are done with a reaction, you quickly set up your next reaction. You want to leave as much time as possible for the reaction. • While you are waiting for the reaction to proceed, you can be setting up for your next trial by measuring out the HCl and Zn and doing the calculations.

  9. 1st Period Lab Groups Sara Isaiah Niamarion Carla Gerald Tumani Chronicle Ashanti Choice Zahra Jane Imani Chibuzo 2 6 5 3 Quay Hydeia Shana Patricia Judy Maria Taylor Justin Joy 4 Amy Robert Arielle Mariama Tatiana Rahamanh Jasmine Danielle Kayla Kaylan 7 1

  10. 2nd Period Lab Groups Keanthoy Joe Ajai Nathaly Camille Alan Javonte Jasmine Daija Sergio Ryan Tesia 2 6 5 3 Regan Omari Ahzia Keira Angelique Kayla Lauryn Janiece 4 Chris Aginah Jenna Jared Otis Maya Najae Erick 7 1

  11. 5th Period Lab Groups Hunter Clarissa Kailah Jelani Dreshion Michael K Judah Jamille Kahlia Erik Savon Khamya Victoria 2 6 5 NeTanyah Tajana Darnell Destini Michael G Murrell Chantice Breanna 3 4 Tyrese Courtney Romalle Tiara Tanisha Jocelyn Khyri Badieye 7 1

  12. 6th Period Lab Groups Khalin D’angelo Erica Kyla Bria Teon Nanyamka Jessica Jordin Michael 5 3 4 Julian Arya Cyntrall Nicole Kihinde Ariel Tyler 6 2 Jamie Tenisha Alex Sydney Caylen D’niko 7 1

  13. 8th Period Lab Groups Paul Kennesha Nakia Sam Tayva Tamarha Carl Eriun Tiana Ravion Breanna R 2 6 5 Angela Ebony Brianna S Eric Alexis Courtney Brittany David Elijah 3 4 Keon Charles Abdul Patience Jalaun Maya Sydney Willie 7 1

  14. Monday, March 11th Objective: Students will be able to determine a limiting reactant and calculate a percent yield. Bell Ringer: 2 C4H10 + 13 O2 8 CO2 + 10 H2O How many grams of H2O are formed from 5.5 g of O2? 5.5g O2 x 1mol O2x 10molH2Ox 18 g H2O= 32 g O2 13 mol O2 1mol H2O 2.4g H2O =5.5 x 1 x 10 x 18 g H2O= 32 x 13 x 1

  15. Obj:SWBAT determine a limiting reactant and calculate a percent yield. Date: 3/11/2013 What is a Limiting Reactant? • In a chemical reaction, the amount of product that can be produced is limited by the reactant that can produce the least amount of products based upon the ratios in which they react. • The reactant that produces the least amount of product is called the limiting reactant. • How many bikes can be made if you have: • 18 wheels • 10 handlebars • 12 seats • 10 frames Example • You can make 9 bikes • Wheels are the limiting reactant.

  16. Example #1 • All limiting reactant problems start with a balanced chemical equation. 4 FeCl3 + 3 O2  2 Fe2O3 + 6 Cl2 How many moles of Cl2can be produced if 5 moles of FeCl3 react with 4 moles of O2? • FeCl3 is the limiting reactant because 7.5 moles of Cl2 were produced. • O2 was the excess reactant. 5 mol FeCl3 x 6 mols Cl2 = 4 mols FeCl3 7.5 mol Cl2 4mol O2 x 6 mols Cl2= 3 moles O2 8mol Cl2

  17. Example #2 2 C2H6 + 7 O2  4 CO2 + 6 H2O How many grams of H2O can be produced if 15 grams of C2H6 react with 45 grams of O2? Molar masses: C2H6 = 30 g/mol; O2 = 32 g/mol; H2O = 18g/mol 18 gH2O = 1mol H2O 1mol C2H6 x 30 g C2H6 6 mol H2O x 2 mol C2H6 27 g H2O 15 g C2H6 x 21.7 g H2O 18 g H2O = 1mol H2O 6 mols H2Ox 7moles O2 45 g O2 x 1 mol O2x 32 g O2 • O2 is the limiting reactant • C2H6 is the excess reactant

  18. Obj:SWBAT determine a limiting reactant and calculate a percent yield. Date: 3/11/2013 What is Percent Yield? • The ratio of the actual yield (what you actually produced) to the theoretical yield (what you calculated) for a chemical reaction expressed as a percentage. • It’s a measure of the efficiency of the reaction. (think of it like a grade for the reaction) Percent Yield = Actual Value x 100 Theoretical Value Example What would be the percent yield of the previous reaction if only 20 g of H2O were produced? 92.2 % Percent Yield = 20 g H2O x 100 = 21.7 g H2O

  19. Set-Up Help Balanced ChemEq: aA bB • Calculate the molar masses of both compounds in the problem • Convert: remember Given and Want Given(g) x1 molGivenx molWant x Mol.massWant = Mol.massGivenmolGiven 1 molWant • Multiply everything in numerator. • Multiply everything in the denominator • Divide Numerator by Denominator. `

  20. Set-Up Help Balanced ChemEq: aA bB • Mole A Mole B  Gram B: Mole A xb Mole B x Molar Mass B = Gram B a Mole A 1 molB • Gram A  Mole A  Mole B Gram A x 1Mole Ax b Mole B= Mole B Molar Mass A amolA

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