09_19 Molar Mass - Alliance Ouchi-O`Donovan 6

Report
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?

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