1. The Mole

2.  Matter can be measured in 3 ways:  Counting particles  Mass  Volume

3.  SI unit, measures the amount of substance  602,213,670,000,000,000,000,000  A mole of pennies would be $6,022,136,700,000,000,000,000  six sextillion, twenty-two quintillion, one hundred thirty-six quadrillion, seven hundred trillion dollars  6.02 x 10 23

4.  The number of representative particles in one mole of a pure substance

5.  Atoms  Right off periodic table  7 elements exist only as diatomic molecules  (H 2 N 2 O 2 F 2 Cl 2 Br 2 I 2 )  Molecules  Covalently bonded  Formula Units  Ionic Compounds

6.  Fe = 6.02 x 10 23 atoms  H 2 O = 6.02 x 10 23 molecules  CaCl 2 = 6.02 x 10 23 formula units

7.  Conversion factor =  6.02 x 10 23 particles 1 mole How many atoms are in 2.00 mol of argon?

8.  How many molecules are in 7.25 mol of carbon dioxide?  How many formula units are in 3.15 mol of sodium oxide?

9.  How many moles are in 1.62 x 10 23 atoms of argon?  How many moles are in 4.35 x 10 24 molecules of dinitrogen triflouride?

10.  Mass of one mole of a substance  g/mol  Mass of atoms is found on the periodic table  K =  Mass of compounds must be calculated  H 2 0  CO 2

11.  What is the molar mass of barium acetate?  What is the molar mass of ammonium sulfate?

12.  How many moles are in 12.5 g of Carbon dioxide?  How many moles are in 83.2 g of H 2 SO 4 ?

13.  What is the mass in grams of 1.5 mol of sodium chloride?  What is the mass in grams of 0.774 mol of oxygen?

14.  STP  Standard temperature and pressure  T = 0 o C  P = 1 atmosphere (atm)

15.  At STP 1 mole of gas occupies a volume of 22.4L  22.4L = molar volume of a gas  22.4L of a gas contains 6.02 x 10 23 particles of that gas.

16.  What is the volume of 1.50 mol of nitrogen at STP?  What is the volume of 3.75 mol of helium at STP

17.  How many moles are in 75.3 L of water vapor at STP?  How many moles are in 250 L of nitrogen dioxide at STP?

18.  Must ALWAYS go to moles first

19. Moles ParticlesVolumeMassParticlesVolumeMass

20.  How many atoms are in a 44.3 g piece of iron?  What is the volume of 5.24 x 10 22 molecules of iodine?

21.  What is the volume of 68.4 g of fluorine gas at STP?  How many molecules are in 0.75 L of nitrogen gas at STP?

22.  What is the mass in grams of 2.301 L of sodium phosphate?  What is the volume of 17.3 g of NH 3 gas at STP?

23.  The percent by mass of each element in a compound  The percents of all the elements should add up to 100

24. 1. Find the total molar mass of each element in the compound. 2. Find the molar mass of the entire compound. 3. Divide the total molar mass of each element by the molar mass of the compound then multiply by 100 4. Check that all your percentages add up to 100

25. 1. Total mass of C = total mass of F = 2. Mass of compound C 3 F 6 = 3. % of C = % of F = 4. Check your work!

26.  What is the percent composition of H 2 SO 4 ?

27.  Empirical formula – shows the smallest whole- number ration of atoms in a compound  Molecular formula – gives the actual number of each kind of atom in a molecule  C 6 H 12 O 6

28. 1. Change % to g (assume 100 g of compound so 30% = 30 g) 2. Convert each element from g to moles 3. Divide each mole amount by the smallest number from step 2 4. Change to a whole number = subscript in empirical formula

29. 1. g of N = g of O = 2. Convert to moles 3. Divide 4. Formula =

31.  To find the molecular formula you must know  Empirical formula  Molar mass of compound  Can be the same as the empirical formula but often is not

32. 1. Calculate the mass of the empirical formula 2. Divide molar mass of compound by mass of empirical formula 3. Multiply each subscript in the empirical formula by the answer from step 2

33. 1. Mass of NO 2 = 2. 3. Molecular formula =

34.  An unknown compound contains 58.5% carbon, 9.8% hydrogen, and 31.4% oxygen. Its molar mass is 102 g/mol. What are its empirical and molecular formulas?