1. DO NOW Q: List everything that you know about the mole and its uses.
March 20
DO NOW Q:
List everything that you know about the mole and its uses.
Announcements:
Important Dates: (that means…write it down in your calendar)

2. Unit 6 Notes-

3. Chemical Measurements
What are all the different ways in which we make measurements in chemistry?
Counting
Massing
Measuring out volume, etc.
Which technique we employ is determined, in large part, by our purpose.

4. It is also necessary, when determining which technique to use, to consider what type of measurement is easiest to make or even feasible. Consider the chemical reaction below: Cl2(g) + 2KI(aq) —> 2KCl(aq) + I2 (s) The number of molecules and formula units that interact is know, but it’s impossible to actually study this reaction at the atomic level in a chemistry laboratory; we cannot count out just one or two atoms or molecules of anything! We have to use another way to measure out the necessary quantities of chlorine and potassium iodide.

5. The Mole
A mole is a quantity of something just like a dozen (12), gross (144), or ream (500).
We use these more familiar quantities to count out large quantities because it’s more convenient. We can convert from the individual item to the quantity units by using simple conversion factors.
Try the problems below using factor labeling:
5 dozen eggs = ______________ eggs
1152 pencils = _______________ gross of pencils
5000 pieces of paper = ______________reams of paper

6. 5 dozen eggs = ______________ eggs 1152 pencils = _______________ gross of pencils 5000 pieces of paper = ______________reams of paper

7. mole = the number of atoms of an element that would be found in, say, grams of carbon-12 or grams of nitrogen-14 (the molar mass) mole = ____________ atoms (this number is called “________________ number”) mole =_________ L of any gas at STP (standard temperature and pressure: 273 K and 1.0 atm)
6.02 x 1023
Avogadro’s
22.4

8. one atom of Ar = _______ amu
This means that we can use the atomic masses on the periodic table to convert instantly to grams. The mass of one mole of atoms is called the molar mass. Use the periodic table to determine the following:
 one atom of Ar = _______ amu
one mole of Ar atoms =______ g = molar mass of Ar
one atom of Na = __________ amu
one mole of Na atoms ______ g = molar mass of Na
 one atom of Pb =_______ amu
one mole of Pb atoms= ________ g molar mass of Pb
one atom of B = ________ amu
one mole of B atoms = ________ g = molar mass of B
39.95
207.2
39.95
207.2
22.99
10.81
10.81
22.99

9. Simple Conversions Using Mole Equivalencies
We use mole equivalencies to convert:
• moles to _______ --> 1 mole of element = _________
• moles to the number of _______ -->
1 mole of element = ____________
• moles of gas to __________ --> 1 mole of gas = _______
For example:
1.50 mol Na = ________ Na
1.50 mol Na x g Na = g Na = g Na (sig figs!)
1 mol Na
grams
Atomic mass in grams
particles
6.02 x 1023 particles
Liters of gas
22.4 L
34.5g

10. Practice 1: Do the following conversions using the mole equivalencies above. Use factor labeling and show your work. a) 2.0 mol Ni = _______ g Ni b) ___2.000___mol C = g C c)…Helium… d) ___________mol Ca = 4.75 x 1026 atoms Ca e) mol Xe = __________L of Xe

11. Atomic masses of elements  formula mass of a compound  molar mass of a compound
We can work easily with the mass of a compound in the same way we do with elements. Determine the mass of a unit of sodium chloride or calcium fluoride by adding up _______________of the component elements in their proper ____________. The sum is called the ________________
one atom of Na = ___________ amu one atom of Ca = ____________ amu
one atom of Cl = ____________ amu two atoms of F = ____________ amu
formula mass of NaCl = _______amu formula mass of CaF2 = ________ amu
atomic mass
ratios
formula mass
23.0
40.1
2 (19.0)
35.5
58.5
78.1

12. molar mass of CaF2 = ________ g molar mass of H2O _________ g
The molar mass of a substance is determined the same way, but you are finding the mass of ________ instead of the mass of just one ________ (for a covalent compound) or one __________ (for an ionic compound).
molar mass of NaCl = ________ g
molar mass of CaF2 = ________ g
molar mass of H2O _________ g
molar mass of K2SO4 = _______ g
molar mass of SO3 _________ g
molar mass of Cl2 = __________ g
one mole
molecule
formula unit
58.5
78.1
18.016
174.3
80.1 71

13. Practice 2: More simple conversions using mole equivalencies a. 2
Practice 2: More simple conversions using mole equivalencies a. 2.0 mol S02 = ___________g SO2 b. _____________ mol F2 = 1.4 L F2 c x 1023 molecules H2O = ______________ mol H2O d mol Fe = ______________ atoms Fe f g CO2 = ______________ molecules CO2 Multi-step conversions, using mole equivalencies Conversions involving moles, like other conversions, can involve more than one step. When this is the case, it is convenient for you to first plan the conversion. Example problem: 2.3 x 1026 molecules H2 = _____ L of H2 2.3 x 1026 molecules H2 x____ 1 mol H2 x 22.4 L H2 = 6.02 x 1023 molecules H2 1 mol H2 Practice 3: (answer in your composition book): g BeCl2 = __________ formula units BeCl g H2O = __________ molecules H2O x 1023 molecules I2 = ____________ moles I L CH4 = _____________ g CH g NaF = ____________ formula units NaF x 1028 atoms Ar = ____________ L Ar x 1022 molecules Br2 = __________________ g Br L CO = ______________ molecules CO 9. How many atoms of uranium are in 5.00 g of uranium? 10. What is the volume of 2.6 g of nitrogen gas? 11. What is the mass of 1.0 x 1024 molecules of sulfur dioxide? 12. What is the mass of Neon in a sign when the gas tubes have a total volume of 166 mL?

15. The Mole Map