All Roads Lead to the Mole

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Jasmin Park
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CHEMICAL QUANTITIES Chemical Quantities Dozen: Baker as Mole: Chemist Measuring

dozen = 1 box doughnuts (volume) All Roads Lead to the Mole Measuring steam (H O

in math and physics Discovered that equal volumes of different gases contained an

9 years after his death, Joseph Loschmidt determined a constant and named it after

1 CHEMICAL QUANTITIES Chemical Quantities Dozen: Baker as Mole: Chemist Measuring doughnuts: o 1 dozen = 1 doughnuts (count) o 1 dozen = 500 g doughnuts (mass) o 1 dozen = 1 box doughnuts (volume) All Roads Lead to the Mole Measuring steam (H O gas): o 1 mole = 6.0 x 3 H O molecules (count) o 1 mole = 18.0 g H O (mass) o 1 mole =.4 L H O (volume) at STP Count Amedeo Avogadro Lawyer who became interested in math and physics Discovered that equal volumes of different gases contained an equal number of particles. 9 years after his death, Joseph Loschmidt determined a constant and named it after Avogadro. AVOGADRO S CONSTANT = 6.0 x 3 Not to be confused with the delicious fruit AVOGADRO S CONSTANT = 6.0 x 3 1 mole = 6.0 x 3 particles 1 mole = molar mass (grams) 1 mole (of a gas at STP) =.4 L The MOLE is to chemists as the DOZEN is to bakers. 1

Believe it or not, students all over the country celebrate National Mole Day! National Mole Day Foundation, INC.

0 x 3 Grains of Sand: Would be more than all of the sand on Miami Beach. 6.

0 x 3 Watermelon Seeds: Would be found inside a melon slightly larger than the moon. 6.

0 x 3 Donut Holes: Would cover the earth and be 5 miles (8 km) deep.

2 Believe it or not, students all over the country celebrate National Mole Day! National Mole Day Foundation, INC. Mole Day 5 Pound Bag of Sugar contains 6.6 moles Of C 1 H O 11 1 Liter bottle of Water contains 55.5 moles H x 3 Grains of Sand: Would be more than all of the sand on Miami Beach. 6.0 x 3 Blood Cells: Would be more than the total number of blood cells found in every human on earth. 6.0 x 3 Watermelon Seeds: Would be found inside a melon slightly larger than the moon. 6.0 x 3 Pennies: Would make at least 7 stacks that would reach the moon. 6.0 x 3 Donut Holes: Would cover the earth and be 5 miles (8 km) deep. Types of Representative Particles Volume Mass Molecules (breaks down into atoms) Atoms Formula Units (breaks down into ions) Formula Units Ions R.P. Molecules Atoms Ions Naming Representative Particles Naming Representative Particles Examples: Name the representative particle for each substance given. For each molecule, state how many atoms are present. For each formula unit, state how many ions make up the ionic compound. Pure Substance H + : ION Element Compound Cl : MOLECULE ATOMS per molecule Monotomic Polyatomic Molecular Ionic C H 6 : MOLECULE 8 ATOMS Charged Neutral MOLECULE MOLECULE FORMULA UNIT Cu(NO 3 ) : FORMULA UNIT 3 IONS per Form.U. ION ATOM Al: ATOM NaCl: FORMULA UNIT IONS per Form.U.

3 Mole R.P. Calculations R.P. Example 1: How many moles are in 1.4 x molecules of H O? 1 mole = Avogadro s Number = 6.0 x 3 R.P. s 1.4 molecules HO molecules H O R.P R.P. R.P. = 0.03 mol HO R.P. Example : How many representative particles are in.6 mol CO? R.P. Example 3: How many atoms are in 5. mol CO? 3.6 mol CO 6.0 molecules CO CO =1.6 4 molecules CO 3 5. mol CO 6.0 molecules CO CO = atoms 3 atoms ecule CO MASS of one MOLE Gram atomic mass (gam): the atomic mass (the mass in one mole of a substance) of an element expressed in grams. Gram molecular mass (gmm): the atomic mass of one mole of a molecular compound. Gram formula mass (gfm): the sum of the atomic masses of the atoms that are in the formula of a compound. gam, gfm, gmm examples: Problem: Give the gram atomic mass of hydrogen. Solution: H = 1H = 1(1.0) = 1.0 g/mol Problem: Give the gram molecular mass of hydrogen. Solution: H = H = (1.0) =.0 g/mol Problem: Find the gram formula mass for H SO 4. Solution: H SO 4 = H + 1S + 4O = (1.0) (16.0) = 98.1 g/mol 3

Molar Mass a.k.a. Molecular Weight (MW) MW Example 1: molar mass = mass of 1 mole of substance Molar mass can be determined by adding up the atomic masses from the periodic table. Find the MW of CH 4.

4 Molar Mass a.k.a. Molecular Weight (MW) MW Example 1: molar mass = mass of 1 mole of substance Molar mass can be determined by adding up the atomic masses from the periodic table. Find the MW of CH 4. = 1C + 4H = (1.0) = 16.0 g/mol MW Example : MW Example 3: Find the MW of Mg(OH). =Mg + O + H =4.3 + (16.0) + (1.0) =58.3 g/mol Find the MW of MgSO 4 7H O. =Mg + S + 4O + 7(H O) = (16.0) + 7(18.0) =46.4 g/mol What is the mass of one mole of table salt (NaCl)? a) 3.0 g b) 35.5 g c) 58.5 g d) 0.0 g Mole Mass Calculations 1 mole = molar mass (MW) in grams Atomic mass Na = 3.0 g/mol Atomic mass Cl = 35.5 g/mol Mass of one mole of NaCl = = 58.5 g molar mass (g) molar mass (g) Mass 4

This image cannot currently be displayed. Mass Example 1: Mass Example 1: How many grams are in 7.0 moles of dinitrogen trioxide? Dinitrogen trioxide = N O 3 MW of N O 3 = N + 3O = (14.0) + 3(16.

5 This image cannot currently be displayed. Mass Example 1: Mass Example 1: How many grams are in 7.0 moles of dinitrogen trioxide? Dinitrogen trioxide = N O 3 MW of N O 3 = N + 3O = (14.0) + 3(16.0) = 76.0 g/mol 1 mole = 76.0 g N O 3 7.0mol N O 76.0g 1.00mol 3 = 547g N O 3 Mass Example : Mass Example : Find the number of moles in 9. g of iron(iii) oxide, Fe O 3. Iron (III) oxide = Fe O 3 MW of Fe O 3 = Fe + 3O = (55.8) + 3(16.0) = g/mol 1 mole = g Fe O 3 9.g Fe O 1.00mol 159.8g 3 = 0.577mol Fe O 3 What is the mass of 3.7 moles of NaCl? a) 15.8 g b) 58.5 g c) 16.5 g d) 6.0 x 3 g What is the mass of one mole of water (H O)? a) 3.0 g b) 16.0 g c) 17.0 g d) 18.0 g 3.7mol NaCl 58.5g NaCl = 16.5g 1 mol Atomic mass H = 1.0 g/mol Atomic mass O = 16.0 g/mol Mass of one mole of H O = (1.0) = 18.0 g How many moles are in 15 g of water? a) mol b) 8.44 mol c) 736 mol d) 6.0 x 3 mol Mole Volume Calculations 1 mole =.4 L of gas at STP STP = standard temperature and pressure (0 C & 1 atm) 15g H 1 O 18.0g H O = 8.44mol.4 L.4 L Volume 5

6 Volume Example 1: Volume Example 1: Determine the volume, in liters, of mol of SO gas at STP mol SO (g).4l =13.4L SO Volume Example : Volume Example : Determine the number of moles in 33.6 L of He gas at STP. 33.6L He(g).4 L = 1.50 mol He Density Density Example (part A): Density = Mass / Volume When given the density of an unknown gas, one can multiply by the molar volume to find the MW. The MW can allow for identification of the gas from a list of possibilities. The density of an unknown gas is.054 g/l. (a) What is the molar mass? density molar volume = molar mass.054g.4l = 46.01g/mol L Density Example (part B): The density of an unknown gas is.054 g/l. (b) Identify the gas as either nitrogen, fluorine, nitrogen dioxide, carbon dioxide, or ammonia. MW = 46.0 g/mol (from part a) Nitrogen = N = (14.0) = 8.0 g/mol Fluorine = F = (19.0) = 38.0 g/mol Nitrogen dioxide = NO = (16.0) = 46.0 g/mol Carbon dioxide = CO = (16.0) = 44.0 g/mol Ammonia = NH 3 = (1.0) = 17.0 g/mol Mixed Mole Conversions 1 mole = 6.0 x 3 RP s = MW =.4 L of All Roads Lead to the Mole. Always convert to units of moles first when converting between grams, liters, and representative particles. 6

7 Mixed Mole Example 1: Mixed Mole Example : How many carbon atoms are in a 50.0-carat diamond that is pure carbon? Fifty carats is the same as.0 g. 3.0g 6.0 atoms 1.0g C C 3 = 5.0 atoms C How many atoms are in.0 g of water? 3.0g H O 6.0 molecules 18.0g = atoms ecule atoms 7

NOTES: Chemical Quantities (The Mole / Molar Mass) All Roads Lead to the Mole!!

NOTES: Chemical Quantities (The Mole / Molar Mass) All Roads Lead to the Mole!! NOTES: 10.1-10.2 Chemical Quantities (The Mole / Molar Mass) All Roads Lead to the Mole!! What is a mole? A unit of measure used to count atoms, molecules, or ions A number: 6.02 x 10 23 (Avogadro s number)