Chemistry I notes October Mole Calculations 22 4

Chemistry I notes October

Mole Calculations (22. 4 L/mol) (periodic table) Molar Volume Mass (g) Molar Mass Amount (mol) Volume @ STP (Liters) Avogadro’s Number (6. 02*1023 particles/mol) Particles (atoms, molecules, trees, etc. )

Mole Calculations A sample of 3. 35*1022 atoms of gold contains how many grams of gold? 197 g Au = 1 mole Au = 6. 02*1023 atoms Au Calculator Moment: (3. 35 E 22)÷(6. 02 E 23)= X(197)=

Mole Calculations A sample of 74. 6 g of boron (rhymes with moron) contains how many atoms of boron? 11 g B = 1 mole B = 6. 02*1023 atoms B Calculator Moment: (74. 6) (11)= X (6. 02 E 23)=

Molar Volume • For any gas at standard conditions, 1 mole of gas occupies exactly 22. 4 liters of space. Standard Temperature Standard Pressure 0 ºC 1 atmosphere 32 ºF 760 torr 273. 15 K 760 mm Hg 1. 01325 bar 1. 01325*105 Pa 14. 70 psi 29. 92 in Hg

Mole Calculations What is the mass of a 78. 4 L sample of xenon gas measured at standard temperature (0ºC) and standard pressure (760 mm Hg)? 131 g Xe = 1 mole Xe = 22. 4 L Xe = 6. 02*1023 atoms Xe ONLY @ STP! Calculator Moment: (78. 4) ( 22. 4)= X(131)=

Another mole calculation using a gas 205 grams of argon gas is equal to how many liters of the gas at STP? 40 g Ar = 1 mole Ar = 22. 4 L Ar = 6. 02*1023 atoms Ar ONLY @ STP! 205 g Ar = 114. 8 L of Ar

One more mole calculation using a gas What is the volume in liters of 8. 25 X 1025 molecules of nitric oxide gas at standard temperature and pressure? 8. 25 X 1025 molecules = 3070 L of NO

One last mole calculation using a gas 82. 3 grams of sulfur dioxide is equal to what volume of the gas at STP? Formulas for sulfur dioxide is SO 2 Molar mass of sulfur dioxide is 64 g/mole 82. 3 g SO 2 = 28. 81 L of SO 2

Molar Mass for Molecules 1) Read the formula. 2) Determine each element’s molar mass. 3) Multiply the molar mass by the number of atoms present. 4) Add your calculations together. Al 2(SO 3)3 HBr + 1 g/mol H 80 g/mol Br 81 g/mol HBr 2*27 g/mol Mg + 3*32 g/mol S 9*16 g/mol O 294 g/mol Al 2(SO 3)3

Mole Calculations with Compounds Grams Moles 35. 1 grams of Fe. SO 4 is equal to how many moles?

Mole Calculations with Compounds Moles Grams 10. 7 moles of acetylsalicylic acid (C 9 H 8 O 4) is equal to how many grams?

Mole Calculations - Compound How many molecules of water are present in a 25. 36 g sample? H 2 O contains 2 Hs and 1 O. 2*(1 g/mol H) + 16 g/mol O 18 g H 2 O = 1 mol H 2 O = 6. 02*1023 molecules H 2 O Calculator Moment: (25. 36) (18)= X(6. 02 E 23)=

Mole Calculations- Compound How many grams of bismuth(III) sulfite are contained in 2. 88 X 1021 molecules of this compound?

Mole Calculations (22. 4 L/mol) (periodic table) Molar Volume Mass (g) Molar Mass Amount (mol) Volume @ STP (Liters) Avogadro’s Number (6. 02*1023 particles/mol) Particles (atoms, molecules, trees, etc. )

Additional Practice 1) A stick of chalk contains 14. 8 g of calcium carbonate. How many moles of the compound are present? 2) Convert 35. 0 g of iron(III) sulfate to its a) number of moles b) number of molecules

3) Acetylsalicylic acid (C 16 H 12 O 6) is the active ingredient in aspirin. What is the mass of 0. 287 moles of acetylsalicylic acid? 4) What is the mass of 10. 0 L of propylene at STP?

Part of the Whole Compound 5) How many atoms of hydrogen are present in 4. 00 L of propylene at STP? propylene = 4. 00 L C 3 H 6 1 mole C 3 H 6 22. 4 L C 3 H 6 6 moles H 1 mole C 3 H 6 6. 02 X 1023 atoms H 1 mole H = 6. 45 X 1023 atoms H

6) How many grams of CARBON are present in 102. 8 grams of calcium hydrogen oxalate? 7) How many grams of HYDROGEN are present in 72. 8 grams of magnesium dihydrogen phosphate? 8) 40. 5 liter of dinitrogen bromide at STP contains how many grams of NITROGEN?

Molar Mass 11) 0. 73 moles of a compound weighs 93. 4 grams. What is this compound’s molar mass? Molar mass has units of grams/mole grams = moles grams/mole

Molar Mass 12) A sample of a compound containing 1. 45 moles and weighs 430. 65 grams. a) What is the molar mass of the compound? b) Which of these compounds could it be? 1) beryllium iodide, 2) calcium fluoride or 3) barium bromide

Molar Mass 13) A sample that contains 3. 01 X 1023 molecules of a substance weighs 92. 5 grams. a) Find the molar mass of the compound. b) Given the following compounds, which one is likely to be the substance? Ca(Cl. O 2)2, Cd(Cl. O 2)2, Fe(Cl. O 2)2, or Cu(Cl. O 2)2

14) An unknown compound has a mass of 53. 75 grams, which is 0. 25 moles of the compound. The compound contains a metal bonded to a sulfate ion. What is the unknown compound?