Date post: | 23-Jun-2015 |
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Technology |
Upload: | mrheffner |
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Launch: 11/30 Grab your binder and immediately take a seat!
Place homework (practice questions), binder paper, and a pen/pencil on your desk.
Today’s Objective: I can convert between grams and moles using molecular mass as a conversion factor
Tonight’s HW: Finish practice question worksheet
Launch 11/30
1. Calculate the molecular mass of H2 (include units!).
Launch 11/30
2. Calculate the molecular mass of NO3 (include units!).
Launch 11/30
3. Calculate the molecular mass of Mg(ClO2)2 .
Announcements Quiz on Friday
The mole Conversions
Unit exam in 2 weeks
Block 5 earned the party this Friday
How many moles? - Part II Mr. Heffner 11/30/09
How many moles? Molar mass
used to convert between grams and moles units = grams/mole
can be shown as a fraction
Molar mass of H2 = 2.02 g/mol
2.02 grams 1 mole
1 mole 2.02 grams
or
How many moles? There is a 3-step process:
1. Write down the starting unit. 2. Calculate molecular mass and turn it into a
conversion factor with the starting units on the bottom.
3. Cancel units and multiply across the top and bottom.
Example #1: mol g How many grams of H2 are there in 2 moles of H2?
Step #1: Write down the starting unit.
2 moles
How many grams of H2 are there in 2 moles of H2?
Step #2: Calculate molecular mass and turn it into a conversion factor with the starting units on the bottom.
2.02 grams 1 mole
Example #1: mol g
2 moles X =
How many grams of H2 are there in 2 moles of H2?
Step #3: Cancel units and multiply across the top and bottom.
2.02 grams 1 mole
Example #1: mol g
2 moles X =2 X 2.02 grams
1
= 4.04 grams
units!
Example #2: g mol How many moles of CO are there in 14.00 grams of CO?
Step #1: Write down the starting unit.
14.00 grams
How many moles of CO are there in 14.00 grams of CO?
Step #2: Calculate molecular mass and turn it into a conversion factor with the starting units on the bottom.
1 mole 28.01 grams
Example #2: g mol
14.00 grams X =
How many moles of CO are there in 14.00 grams of CO?
Step #3: Cancel units and multiply across the top and bottom.
1 mole 28.01 grams
Example #2: g mol
14.00 grams X =14.00 X 1 mole
28.01
= ~.5 moles
units!
Partner Teaching Partner A teaches Partner B
Partner A writes and narrates Partner B listens
Partner B completes the problem on own paper
Switch!
1. How many moles of O2 are there in 64.00 grams of O2?
2. How many grams of NO2 are there in 4 moles of NO2?
Foldable Define the following terms:
Mole Avogadro’s number
Molecular mass Conversion factor Starting unit
Practice Questions Practice question worksheet
Exit Slip 1. What is the molar mass of Al(OH)3?
a. 43.99 g/mol b. 78.01 g/mol
c. 300.03 g/mol d. 303.00 g/mol
Exit Slip 2. Which of the following is not a correct way to
represent the molecular mass of CH4?
a.
b.
c.
d. 16.05 g/mol
1 mole 16.05 grams
16.05 grams 1 mole
16.05 moles 1 gram
Exit Slip 3. Which of the following shows the correct way to
calculate the number of moles in 16.00 grams of O2?
a. 16.00 moles X
b. 16.00 grams X
c. 16.00 grams X
d. 16.00 moles X
32.00 grams 1 mole 1 mole
16.00 grams 1 mole
32.00 grams
16.00 grams 1 mole
Exit Slip 4. How many grams of NH3 are there in 2 moles of NH3?
a. 1.00 moles b. 14.01 grams
c. 17.04 grams d. 34.08 grams
Exit Slip 5. How many moles of N2 are there in 14.01g of N2?
a. .5 moles b. 2 mole
c. 14.01 moles d. 28.02 moles
Homework Finish practice questions