2. Using Chemical Formulas 7-3

3. Beaker Breaker 1.Name the following compounds: CaCl 2 = ____________ P 3 O 6 = _____________ FeCl 2 =______________ H 2 SO 4 =______________

4. Formula Masses sum of the average atomic masses of all the atoms represented in a formula (can be of a molecule, formula unit or ion) Formula mass of H 2 O: 2 (ave. atomic mass of H) +1(ave. at. mass of O) = 2(1.01 amu) + 1(16.00 amu) = 2.02 amu + 16.00 amu = 18.02 amu

5. Calculate the formula mass of the following: sulfuric acid calcium nitrate phosphate ion magnesium chloride

6. sulfuric acid 98.09 amu H 2 SO 4 calcium nitrate 164.10 amu Ca(NO 3 ) 2 phosphate ion 94.97 amu PO 4 3- magnesium chloride 95.21 amu MgCl 2

7. Molar Masses sum of the masses of the elements present in a mole of the molecules or formula units that make up a compound Molar mass of water, H 2 O: 1 mole H 2 O = 2 mol H + 1 mol O 2 mol H x 1.01 g H = 2.02 g H 1 mol H 1 mol O x 16.00 g = 16.00 g O 1 mol O 18.02 g Molar mass of water = 18.02 g/mol

8. What is the molar mass of… aluminum sulfide sodium nitrate barium hydroxide

9. What is the molar mass of… aluminum sulfide Al 2 S 3 150.17 g/mol sodium nitrate NaNO 3 85.00 g/mol barium hydroxide Ba(OH) 2 171.35 g/mol

10. Beaker Breaker 1.Name the following the compounds: CaBr 2 =_______________ H 3 PO 3 =_______________ C 3 I 7 =_________________ CuCl 3 = _______________

12. What is the mass, in grams, of 0.50000 moles of barium hydroxide? Given: 0.500000 mol Ba(OH) 2 Find: g Ba(OH) 2 Know: 1 mol Ba(OH) 2 =171.35 g Ba(OH) 2 0.500000 mol Ba(OH) 2 x 171.35 g Ba(OH) 2 1 mole Ba(OH) 2 = 85.675 g Ba(OH) 2 Using Molar Mass as a conversion factor between “moles” ↔ “mass”

13. How many moles are in 6.60 g of ammonium sulfate? Given: 6.60g (NH 4 ) 2 SO 4 Find: 0.0499 mol (NH 4 ) 2 SO 4 Know: 1 mol(NH 4 ) 2 SO 4 = 132.17 g (NH 4 ) 2 SO 4 (NH 4 ) 2 SO 4 = 2(N) + 8(H) + 1(S) + 4(O) = 2(14.01) + 8(1.01) + 1(32.07) + 4(16.00) 132.17 g/mol 6.60g (NH 4 ) 2 SO 4 x 1 mol(NH 4 ) 2 SO 4 132.17 g (NH 4 ) 2 SO 4 = 0.0499 mol (NH 4 ) 2 SO 4 (4.99 x 10 -2 mol)

15. Remember…. 1 mole = 6.02 x 10 23 “things” How many molecules are in 50.0 g of water? Given: 50.0 g H 2 O Find: molecules H 2 O Know: 1 mol H 2 O = 18.02g 1 mol H 2 O = 6.02 x 10 23 molecules H 2 O 50.0 g H 2 O x 1 mol H 2 O x 6.02 x 10 23 molecules 18.02 g H 2 O 1 mol H 2 O = 1.67 x 10 24 molecules H 2 O

16. White Board Practice with Partners How many moles of compound are there in the following a. 6.60g (NH 4 ) 2 SO 4 b. 4,500g Ca(OH) 2

17. Answers A. 0.0500mol B. 61mol

18. White Board Practice with Partners How many molecules are there in the following: a. 25.0g H 2 SO 4 b. 125g of C 12 H 22 O 11

19. Answers A. 1.53 x10 23 molecules B. 2.20 x10 23 molecules

20. Beaker Breaker Write the formulas of the following compounds 1.Nitric Acid =___________ 2.Hydroiodic acid =____________ 3.Magnesium Fluoride =____________ 4.Tetracarbon nonahydride =__________

21. Percentage Composition % = part x 100 whole percentage by mass of each element in a cmpd

22. Find the % copper in copper(I) sulfide % Cu = part Cu x 100 whole Cu 2 S % Cu = mass of Cu in 1 mole of Cu 2 S x 100 mass of 1 mol of Cu 2 S Or...% Cu= mass of Cu in 1 mole of Cu 2 S x 100 molar mass of Cu 2 S Cu 2 S = 159.17 g/mol (molar mass..on bottom) 1 mol Cu 2 S, there are 2 mol Cu = 127.10 g Cu (top term)

23. Find the % copper in copper(I) sulfide Know: % Cu = mass of Cu in 1 mole of Cu 2 S x 100 mass of 1 mol of Cu 2 S 1 mol of Cu 2 S = 159.17 g Cu 2 S 1 mol of Cu 2 S= 2mol Cu = 2(63.546g)= 127.10g = 127.10 g Cu x 100 159.17 g Cu 2 S = 79.852% Cu in Cu 2 S

24. What is the percent carbon in ammonium carbonate? Know : ( NH 4 ) 2 CO 3 % C = grams of C in 1 mol (NH 4 ) 2 CO 3 x 100 molar mass of (NH 4 ) 2 CO 3 1 mol ( NH 4 ) 2 CO 3 = 1 mol C = 12.01 g C 1 mol ( NH 4 ) 2 CO 3 = 96.11 g ( NH 4 ) 2 CO 3 = 12.01 g C x 100 96.11 g = 12.50% C

25. Beaker Breaker 1.Phosphoric acid can be used in orthodontics to roughen the surface of teeth before the placement of braces. Write the chemical formula for phosphoric acid. 2.Explain your method used to arrive to that answer.

26. Homework Check Pg 236 #25 a. NH 4 1+ Ammonium b.ClO 3 - Chlorate c. OH - Hydroxide d.SO 4 2- Sulfate e. NO 3 - Nitrate f.CO 3 2- Carbonate g. PO 4 3- Phosphate h. CH 3 COO - Acetate i. HCO 3 - Bicarbonate j. CrO 4 2- Chromate

27. Mix Review Challenge Write the name or formula of the following: 1.MgSO 3 =______________ 2.Sodium Hydroxide = __________ 3.Nickel (II) Fluoride =___________ 4.P 2 H 3 =__________

28. Answers 1.Magnesium Sulfite 2.NaOH 3.NiF 2 4.Diphosphorus Trihydride

29. Mix Review Challenge Write the name or formula of the following: 5. Sulfurous acid =___________ 6. Copper (II) Chloride =_________ 7. AlPO 4 =____________ 8. TetraSulfur Heptoxide =__________

30. Answers 5. H 2 SO 3 6. CuCl 2 7. Aluminum Phosphate 8. S 4 O 7