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Molar Mass and Chemical Reactions September 19, 2012 Ms. Boon Chemistry Catalyst Pick up your assignment report. Make a list of at least 3 things you are proud of concerning your academic achievements this year. Make a list of at least 3 things you would like to improve about your school work. Shout Outs! (Period 2) The following students demonstrated mastery (3 or 4) of all the Unit 2 standards on their Unit 2 exam: Edgardo Aguilar & Denise Montes The following students have demonstrated mastery of all Unit 2 standards on average: Christian Romo, Zamir Ramirez, Rumaldo Godinez, and Susan Castellanos Shout Outs! (Period 3) The following students demonstrated mastery (3 or 4) of all the Unit 2 standards on their Unit 2 exam: Eduardo Cabral, Irma Castillo, Christopher Orellana, & Diana Portillo The following students have demonstrated mastery of all Unit 2 standards on average: Douglas Garcia, Gerardo Garcia, Christopher Orellana, Diana Portillo, and Andres Valencia Shout Outs! (Period 4) The following students demonstrated mastery (3 or 4) of all the Unit 2 standards on their Unit 2 exam: Karla Giron, Kiemon Gordon & Abel Martinez The following students have demonstrated mastery of all Unit 2 standards on average: Patrick Jones, Antonio Ojeda, Luis Orellana, and Briceida Pacheco Shout Outs! (Period 5) The following students demonstrated mastery (3 or 4) of all the Unit 2 standards on their Unit 2 exam: Luis Ayala, Jonathan Mendez, Alberto Payan, Surmani Sanford, Angel Tapia & Xochilt Villafana The following students have demonstrated mastery of all Unit 2 standards on average: Angel Tapia Shout Outs! (Period 6) The following students demonstrated mastery (3 or 4) of all the Unit 2 standards on their Unit 2 exam: Melissa Alvarez, Kevin Chavez & Sabrina Montgomery The following students have demonstrated mastery of all Unit 2 standards on average: Melissa Alvarez, Kevin Chavez, Deya Garcia, Sabrina Montgomery, & Christine Romo Objectives I can use my periodic table to calculate the molar mass of any element, compound, or molecule. Agenda Catalyst & Shout Outs Homework Review Molar Mass Puzzle Activity Exit Slip HW Review: Read pp. 230-233; problems: pp. 233 #11, pp. 240 #5 & 10(a, b, c, & e) (233) 11. The mass of 6.022 x 1023 molecules of ibuprofen is 206.31 g. (To solve, we must remember that 6.022 x 1023 molecules = 1 mole and that the mass of 1 mole of a molecule is whatever that molecule’s molar mass is. The question gave us the molar mass as 206.31 g/mol.) HW Review: Read pp. 230-233; problems: pp. 233 #11, pp. 240 #5 & 10(a, b, c, & e) 5. What is the ratio of N and H atoms in NH3? 1N:3H For every N atom there are 3 H atoms. HW Review: Read pp. 230-233; problems: pp. 233 #11, pp. 240 #5 & 10(a, b, c, & e) 10(a). Molar mass of CsCl -- Answer: 168.35 g/mol Steps to Solve: (1) Find the molar mass of the individual elements. Use the periodic table. The molar mass is the same as the average atomic mass. Just change the units from amu to g/mol. CsCl is a 1:1 ratio of Cs and Cl (there are no subscript numbers telling us differently) (3) Add the molar masses in the correct ratio. Cl = 35.453 g/mol (2) Use the compound formula to determine how many of each element is in the compound. Cs = 132.905 g/mol 1 mol Cs = 132.90 g 1 mol Cl = 35.453 g 132.90g + 35.453 g = 168.353 g/mol (rounded = 168.35 g/mol) More HW Review: 240 #10 (b) Molar mass of KClO3? Answer: 122.55 g/mol Steps to Solve: (1) Find the molar mass of the individual elements. Use the periodic table. The molar mass is the same as the average atomic mass. Just change the units from amu to g/mol. K = 39.098 g/mol Cl = 35.453 g/mol O = 15.999 g/mol (2) Use the compound formula to determine how many of each element is in the compound. KClO3 1K: 1Cl: 3O (3) Add the molar masses in the correct ratio. 1 mol K = 39.098 g 1 mol Cl = 35.453 g 3 mol O = 15.999 g x 3 = 47.997 g 39.098 g + 35.453 g + 47.997 g = 122.55 g/mol (c) Molar mass of C6H12O6? Answer: 180.18 g/mol (e) Molar mass of C2H5NO2? Answer: 75.08 g/mol Molar Mass Puzzle! Instructions: Work with a partner You will receive a stack of puzzle pieces. Half have an element or compound formula and the other half have the molar mass. Match the formula with the molar mass. Write the answers down. When you think you have all the answers, raise your hand and Ms. Boon will check. Exit Slip 1. What is the molar mass of Potassium? 2. What is the molar mass Potassium Chloride (KCl)? 3. What is the molar mass of ozone (O3)? 4. The molar mass of NaCl is 58.44 g/mol. What is the mass of 2 moles of NaCl? 5. One mole of water contains 6.02 x 1023 molecules. How many water molecules are in 3 moles of water?