1. Chemistry 11
Mr. Warren

3. What is Molar Mass? The mass of one mole of a substance
Symbol: M
Units: g/mol “or” g∙mol-1
One mole of an element has a mass expressed in grams that is numerically equivalent to the element’s average atomic mass.
Element
AAM (amu)
Molar Mass (g/mol)
Boron
10.81
Gold
196.97

4. Finding Molar Mass of HCl
Ex. 1: HCl
Count # of moles
1 mol of HCl contains 1 mol H and 1 mol Cl

5. Finding Molar Mass of C6H12O6
Ex. 2: C6H12O6

6. Questions?
Practice
Page 56
Question’s 16, 17, 18 & 19

7. Chemistry 11 Mr. Warren

8. Mass = (# moles)(molar mass)
m = n M

9. Ex. A beaker has 0.685 mol of K2S. What mass of K2S is in the sample?

10. Try: What mass is 4.3 moles of copper(II) sulfate?

11. From mass to moles
Ex. How many moles of methanol, CH3OH, are in a 21.8g of sample?
Find the molar mass
Solve for moles

12. Solving for # of moles when given the mass of a substance?
Homework Questions
Solving for # of moles when given the mass of a substance?

13. Answers to Homework Questions
n = mol
n = mol
n = mol

14. Question?
If H2O is water, what is H2O4?

15. Washing, Bathing, Drinking, Swimming.

16. Chemistry 11 Mr. Warren

17. Recall
We can find moles of a substance when we know the number of particles it contains and by dividing it by Avogadro’s Number.
n = N NA

18. 2.44 x 1024 atoms of Cu
How many moles of copper?

19. Moles, Mass and # of particles conversions
(atoms, ions, molecules, formula units
Avogadro’s
Constant
Molar Mass
[g/mol]
Moles
[mol]
Mass
[g]

21. Scenario 1: Particles to Mass
STEPS???

22. Example: What is the mass of 2.74 x 1024 formula units of CrPO4?
Find the number of moles using Avogadro’s constant:

23. Example: What is the mass of 2.74 x 1024 formula units of CrPO4?
Find the number of moles using Avogadro’s constant: mol
Find the molar mass of CrPO4:

24. Example: What is the mass of 2.74 x 1024 formula units of CrPO4?
Find the number of moles using Avogadro’s constant: mol
Find the molar mass of CrPO4: g/mol
Solve for mass:

25. Try: Vitamin B, C17H20N4O6 , is also called riboflavin
Try: Vitamin B, C17H20N4O6 , is also called riboflavin. What is the mass of a sample consisting of 7.36 x 1022 molecules of riboflavin?

26. Scenario 2: Mass to Particles
STEPS???

27. Example: How many molecules of bromine chloride, BrCl, are contained in a 2.66 x 10-1 g sample?
1) Find the molar mass:

28. Example: How many molecules of bromine chloride, BrCl, are contained in a 2.66 x 10-1 g sample?
1) Find the molar mass: g/mol
2) Find the number of moles:

29. Example: How many molecules of bromine chloride, BrCl, are contained in a 2.66 x 10-1 g sample?
1) Find the molar mass: g/mol
2) Find the number of moles: x 10-3 mol
3) Find the number of molecules:

30. Try: The artificial sweetener aspartame (Nutra-Sweet) formula C14H18N2O5 is used to sweeten diet foods, coffee and soft drinks. How many molecules of aspartame are present in 225 g of aspartame?

31. Practice Page 63 of textbook Question’s 28, 29 & 30 Footer Text
9/21/2018