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Launch: 12/1 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 moles and atoms using Avogadro’s number as a conversion factor
Tonight’s HW: Finish the back of the practice question worksheet
Launch 12/1 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
Launch 12/1 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
Announcements Quiz on Friday
The mole Conversions
Unit exam in 2 weeks
How many atoms? Mr. Heffner 12/1/09
Review: 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 atoms? Avogadro’s number…
is equal to 6.02 X 1023 atoms/mol can be used to convert between moles and atoms
6.02 X 1023 atoms 1 mole
1 mole 6.02 X 1023 atoms
or
..or particles, or molecules
..or particles, or molecules
How many atoms? There is a 3-step process for conversions:
1. Write down the starting unit. 2. Write the conversion factor with the starting units on
the bottom. 3. Cancel like terms and multiply across the top and
bottom.
Example #1 How many atoms are there in 2 moles of carbon (C)?
Step #1: Write down the starting unit.
2 moles
How many atoms are there in 2 moles of carbon (C)?
Step #2: Write conversion factor with the starting units on the bottom.
6.02 X 1023 atoms 1 mole
Example #1
2 moles X =
How many atoms are there in 2 moles of carbon (C)?
Step #3: Cancel like terms and multiply across the top and bottom.
Example #1
2 moles X =2 X 6.02 X 1023 atoms
1 = 12.04 X 1023 atoms
Ignore
6.02 X 1023 atoms 1 mole
= 1.204 X 1024 atoms
+1
Example #2 How many atoms are there in 1.5 moles of CO2?
Step #1: Write down the starting unit.
1.5 moles
How many atoms are there in 1.5 moles of CO2?
Step #2: Write conversion factor with the starting units on the bottom.
6.02 X 1023 atoms 1 mole
Example #2
1.5 moles X =
How many atoms are there in 1.5 moles of CO2?
Step #3: Cancel like terms and multiply across the top and bottom.
Example #2
1.5 moles X =1.5 X 6.02 X 1023 atoms
1 = 9.03 X 1023 atoms
Ignore
6.02 X 1023 atoms 1 mole
Example #3 How many moles are there in 3.01 X 1023 molecules of CO2?
Step #1: Write down the starting unit.
3.01X1023 molecules
How many molecules are there in 1.5 moles of CO2?
Step #2: Write conversion factor with the starting units on the bottom.
1 mol 6.02X1023 molecules
Example #3
3.01X1023 molecules X =
How many molecules are there in 1.5 moles of CO2?
Step #3: Cancel like terms and multiply across the top and bottom.
1 mol 6.02X1023 molecules
Example #3
3.01X1023 molecules X =3.01 X 1 mol
6.02
= .5 mol
Whiteboards Work in pairs
Trade-off marker every question
You have 60 seconds to solve the question Show all of your work! Don’t forget units!
Lift board only when prompted
How many atoms are there in 1 mole of potassium (K)?
How many molecules are there in .5 moles of HCl?
How many moles of NO are there in 9.03 X 1023 particles?
How many moles of fluorine (F) are there in
12.04 X 1023 atoms?
Practice Questions Practice question worksheet
Exit Slip 1. What is Avogadro’s number?
a. 6.02 X 1024 atoms b. 6.02 X 1023 atoms
c. 3.01 X 1023 atoms d. 1.2 X 1024 atoms
Exit Slip 2. Which of the following shows the correct way to
calculate the number of atoms in 2 moles of O2?
a. 16 moles X
b. 2 moles X
c. 2 moles X
d. 2 moles X
32.00 grams 1 mole
1 mole 16.00 grams
1 atoms 6.02 X 1023 moles
6.02 X 1023 atoms 1 mole
Exit Slip 3. How many atoms of sodium (Na) are in 1 mole?
a. 3.01 X 1023 atoms b. 6.02 X 1023 atoms
c. 12.04 X 1023 atoms d. 1.204 X 1024 atoms
Exit Slip 4. How many molecules of C3OH are in .5 moles?
a. 3.01 X 1023 molecules b. 6.02 X 1023 molecules
c. 9.03 X 1023 molecules d. 1.204 X 1024 atoms
Exit Slip 5. If there are 1.204 X 1024 particles of gold (Au), how
many moles are there? a. .5 moles b. 1 mole c. 2 moles
d. 4 moles
Homework Finish practice questions