Stoichiometry - Mole Concept & Percent Composition PDF

The Mole Concept Ag Lesson 2 Au STOICHIOMETRY  COLLECTION Do you collect stuff and if so how much of that collection do you have? MOLE COLLECTION TERMS: SPECIFIC NUMBER OF ITEMS A DOZEN EGGS = 12 EGGS 1 BUCKET = 6 BEERS...

The Mole Concept Ag Lesson 2 Au STOICHIOMETRY  COLLECTION Do you collect stuff and if so how much of that collection do you have? MOLE COLLECTION TERMS: SPECIFIC NUMBER OF ITEMS A DOZEN EGGS = 12 EGGS 1 BUCKET = 6 BEERS 1 PAPER REAM = 500 SHEETS MOLE ATOMS, MOLECULES, AND PARTICLES = TOO SMALL! HOW MANY? MOLE 1 mole (mol) COLLECTION TERMS: 6.022 x 1023 602214150000000000000000 ATOMS PARTICLES MOLECULES MOLE 1 mole (mol): a collection that contains the same number of particles as there are carbon atoms in 12.01 g of Carbon-12 C12 Number of Particles Atoms in 12 grams in 1 mol of Carbon-12 MOLE 1 mole (mol): a unit of measurement wherein it measures the amount of substance in the number of particles, atoms, and molecules. Avogadro’s Number 6.022 x 1023 Represent quantities MOLE MOLE 1 mole = 6.022 x 1023 particles (atoms, molecules, ions or formula units) 1 mole Na = 6.022 x 1023 atoms 1 mole Na+ = 6.022 x 1023 ions 1 mole NaCl = 6.022 x 1023 formula units 1 mole H2O = 6.022 x 1023 molecules  MOLE C12 Number of Particles in 1 mol Atoms in 12 grams of Carbon-12 Ag C Mass of 1 mol of Mass of 1 mol of Silver? Carbon-12?  MOLE C12 Number of Particles in 1 mol Atoms in 12 grams of Carbon-12 1 MOLE OF WATER HAS THE SAME NUMBER OF MOLECULES TO THE NUMBER OF ATOMS OF 12 GRAMS CARBON-12 BUT DOES NOT WEIGH 12 GRAMS!!  DETOUR DIMENSIONAL ANALYSIS Allow the CONVERSION of ONE UNIT TO ANOTHER AS LONG AS POSSIBLE Involves multiplication and division of conversion factors NUMBER USED TO CHANGE ONE SET OF UNITS TO ANOTHER  DETOUR CONVERSION FACTORS Fractions whose numerator and denominator are the same quantity but expressed in different units. EXAMPLE : 2.54 𝑐𝑚 1 𝑖𝑛 60 𝑠 1 𝑚𝑖𝑛 = = 1 𝑖𝑛 2.54 𝑐𝑚 1 𝑚𝑖𝑛 60 𝑠  DETOUR Determine the CONVERSION FACTOR YOU NEED to perform the calculations 𝐷𝑒𝑠𝑖𝑟𝑒𝑑 𝑈𝑛𝑖𝑡 𝐺𝑖𝑣𝑒𝑛 𝑈𝑛𝑖𝑡 × = 𝐷𝑒𝑠𝑖𝑟𝑒𝑑 𝑢𝑛𝑖𝑡 𝐺𝑖𝑣𝑒𝑛 𝑈𝑛𝑖𝑡 EXAMPLE :  DETOUR 2 years to seconds? 1 year = 365 days 365 𝑑𝑎𝑦𝑠 24 ℎ𝑜𝑢𝑟𝑠 60 𝑚𝑖𝑛𝑢𝑡𝑒𝑠 60 𝑠𝑒𝑐𝑜𝑛𝑑𝑠 2 𝑦𝑒𝑎𝑟𝑠 𝑥 𝑥 𝑥 𝑥 1 𝑦𝑒𝑎𝑟 1 𝑑𝑎𝑦 1 ℎ𝑜𝑢𝑟 1 𝑚𝑖𝑛𝑢𝑡𝑒 = 63,072,000 𝑠𝑒𝑐𝑜𝑛𝑑𝑠 MOLE 1 mole (mol) COLLECTION TERMS: 6.022 x 1023 602214150000000000000000 3 mol H2 = How many molecules? 6.022 𝑥 1023 𝑚𝑜𝑙𝑒𝑐𝑢𝑙𝑒 𝐻2 3 𝑚𝑜𝑙𝑒𝑠 𝐻2 𝑥 1 𝑚𝑜𝑙𝑒 𝐻2 = 1.8066 𝑥 1024 𝑚𝑜𝑙𝑒𝑐𝑢𝑙𝑒𝑠 𝐻2 = 2 𝑥 1024 𝑚𝑜𝑙𝑒𝑐𝑢𝑙𝑒𝑠 𝐻2 MOLE 1 mole (mol) COLLECTION TERMS: 6.022 x 1023 602214150000000000000000 5.0 mol Au = How many atoms? 6.022 𝑥 1023 𝑎𝑡𝑜𝑚𝑠 𝐴𝑢 5.0 𝑚𝑜𝑙𝑒𝑠 𝐴𝑢 𝑥 1 𝑚𝑜𝑙𝑒 𝐴𝑢 = 3.011 𝑥 1024 𝑎𝑡𝑜𝑚𝑠 𝐴𝑢 = 3.0 𝑥 1024 𝑎𝑡𝑜𝑚𝑠 𝐴𝑢 MOLE 1 mole (mol) COLLECTION TERMS: 6.022 x 1023 602214150000000000000000 8.00 mole NaCl= How many formula units? 6.022 𝑥 1023 𝑓𝑜𝑟𝑚𝑢𝑙𝑎 𝑢𝑛𝑖𝑡𝑠 𝑁𝑎𝐶𝑙 8.00 𝑚𝑜𝑙𝑒𝑠 𝑁𝑎𝐶𝑙 𝑥 1 𝑚𝑜𝑙𝑒 𝑁𝑎𝐶𝑙 = 4.8176 𝑥 1024 𝑓𝑜𝑟𝑚𝑢𝑙𝑎 𝑢𝑛𝑖𝑡𝑠 𝑁𝑎𝐶𝑙 = 4.82 𝑥 1024𝑓𝑜𝑟𝑚𝑢𝑙𝑎 𝑢𝑛𝑖𝑡𝑠 𝑁𝑎𝐶𝑙 MOLE 1 mole (mol) COLLECTION TERMS: 6.022 x 1023 602214150000000000000000 How many moles Mg is 3.01 x 1022 atoms of Mg? 1 𝑚𝑜𝑙𝑒 𝑀𝑔 3.01 𝑥 1022𝑎𝑡𝑜𝑚𝑠 𝑀𝑔 𝑥 6.022 𝑥 1023 𝑎𝑡𝑜𝑚𝑠 𝑀𝑔 = 0.04998339422 𝑚𝑜𝑙𝑒 𝑀𝑔 = 0.0500 𝑚𝑜𝑙𝑒 𝑀𝑔 MOLE 1 mole (mol) COLLECTION TERMS: 6.022 x 1023 602214150000000000000000 1.204 x 1024 atoms Au = How many moles? 1 𝑚𝑜𝑙𝑒 𝐴𝑢 1.204 𝑥 1024 𝑎𝑡𝑜𝑚𝑠 𝐴𝑢 𝑥 6.022 𝑥 1023 𝑎𝑡𝑜𝑚𝑠 𝐴𝑢 = 1.999335769 𝑚𝑜𝑙𝑒 𝐴𝑢 = 1.999 𝑚𝑜𝑙𝑒 𝐴𝑢 MOLE MOLE X MOLES Avogadro’s Number PARTICLES ÷ MOLE The subscripts in a formula state The relationship of atoms in the formula. The moles of each element in 1 mol of compound. Glucose C6H12O6 In 1 molecule: 6 atoms C 12 atoms H 6 atoms O In 1 mol: 6 mol C 12 mol H 6 mol O MOLE How many moles O are in 0.150 mol aspirin C9H8O4? 4 𝑚𝑜𝑙𝑒 𝑂 0.150 𝑚𝑜𝑙𝑒 𝐶9𝐻8𝑂4 𝑥 1 𝑚𝑜𝑙𝑒 𝐶9𝐻8𝑂4 = 0.600 𝑚𝑜𝑙𝑒 𝑂 MOLE How many moles C are in 0.250 mol aspirin C9H8O4? 9 𝑚𝑜𝑙𝑒 𝐶 0.250 𝑚𝑜𝑙𝑒 𝐶9𝐻8𝑂4 𝑥 1 𝑚𝑜𝑙𝑒 𝐶9𝐻8𝑂4 = 2.25 𝑚𝑜𝑙𝑒𝑠 𝐶 MOLE How many atoms of O are in 0.150 mol aspirin C9H8O4? 4 𝑚𝑜𝑙𝑒 𝑂 6.022 𝑥 1023 𝑎𝑡𝑜𝑚𝑠 𝑂 0.150 𝑚𝑜𝑙𝑒 𝐶9𝐻8𝑂4 𝑥 𝑥 1 𝑚𝑜𝑙𝑒 𝐶9𝐻8𝑂4 1 𝑚𝑜𝑙𝑒 𝑂 = 3.6132 𝑥 1023 𝑎𝑡𝑜𝑚𝑠 𝑂 = 3.61 𝑥 1023 𝑎𝑡𝑜𝑚𝑠 𝑂 MOLE MOLECULES ATOMS MOLE SAMPLE ATOMS MASS mass A measure of the amount of matter in a particle or object Grams (g) Kilograms (g) mass Relative atomic mass (Ar) Relative formula mass (Mr) Molecular mass Molar mass  mass Relative atomic mass (Ar) or formula mass (Mr) Determined by combining the relative atomic mass of the individual atoms or ions mass Molar mass Mass of 1 mol of a substance (g/mol)  mass Relative Formula Weight Molecular formula mass (FW) Weight (MW) (Mr) Molar mass  mass Calculate the molar mass of the following substances and ions a.) C6H12O6 𝑔 𝑔 𝐶 = 6 𝑥 12.01 = 72.06 𝑚𝑜𝑙𝑒 𝑚𝑜𝑙𝑒 𝑔 𝑔 𝐻 = 12 𝑥 1.01 𝑚𝑜𝑙𝑒 = 12.12 𝑚𝑜𝑙𝑒 𝑔 𝑔 𝑂 = 6 𝑥 16.00 = 96.00 𝑚𝑜𝑙𝑒 𝑚𝑜𝑙𝑒 𝑔 = 180.18 C6H12O6 𝑚𝑜𝑙𝑒  mass Calculate the molar mass of the following substances and ions b.) Mg(NO3)2 𝑔 𝑔 𝑀𝑔 = 1 𝑥 24.31 = 24.31 𝑚𝑜𝑙𝑒 𝑚𝑜𝑙𝑒 𝑔 𝑔 𝑁 = 2 𝑥 14.01 𝑚𝑜𝑙𝑒 = 28.02 𝑚𝑜𝑙𝑒 𝑔 𝑔 𝑂 = 6 𝑥 16.00 = 96.00 𝑚𝑜𝑙𝑒 𝑚𝑜𝑙𝑒 𝑔 = 148.33 Mg NO3 2 𝑚𝑜𝑙𝑒  mass Calculate the molar mass of the following substances and ions c.) MgSO4· 7H2O 𝑔 𝑔 𝑀𝑔 = 1 𝑥 24.31 = 24.31 𝑚𝑜𝑙𝑒 𝑚𝑜𝑙𝑒 𝑔 𝑔 𝑆 = 1 𝑥 32.06 𝑚𝑜𝑙𝑒 = 32.06 𝑚𝑜𝑙𝑒 𝑔 𝑔 𝑂 = 11 𝑥 16.00 = 176.00 𝑚𝑜𝑙𝑒 𝑚𝑜𝑙𝑒 𝑔 𝑔 𝐻 = 14 𝑥 1.01 = 14.14 𝑚𝑜𝑙𝑒 𝑚𝑜𝑙𝑒 𝑔 = 246.51 MgSO4 7H2O 𝑚𝑜𝑙𝑒  mass Calculate the molar mass of the following substances and ions d.) Fe2(SO4)3 𝑔 𝑔 𝐹𝑒 = 2 𝑥 55.85 = 111.70 𝑚𝑜𝑙𝑒 𝑚𝑜𝑙𝑒 𝑔 𝑔 𝑆 = 3 𝑥 32.06 𝑚𝑜𝑙𝑒 = 96.18 𝑚𝑜𝑙𝑒 𝑔 𝑔 𝑂 = 12 𝑥 16.00 = 192.00 𝑚𝑜𝑙𝑒 𝑚𝑜𝑙𝑒 𝑔 = 399.88 Fe2 SO4 3 𝑚𝑜𝑙𝑒  1 𝑚𝑜𝑙𝑒 𝐶19𝐻18𝑁8𝑂5 1.00 𝑔 𝐶19𝐻18𝑁8𝑂5 𝑥 378.40 𝑔 𝐶19𝐻18𝑁8𝑂5 = 0.002642706131 𝑚𝑜𝑙𝑒 𝐶19𝐻18𝑁8𝑂5 = 0.00264 𝑚𝑜𝑙𝑒 𝐶19𝐻18𝑁8𝑂5  65.38 𝑔 𝑍𝑛 0.356 𝑚𝑜𝑙𝑒 𝑍𝑛 𝑥 1 𝑚𝑜𝑙𝑒 𝑍𝑛 = 23.27528 𝑔 𝑍𝑛 = 23.3 𝑔 𝑍𝑛  1 𝑚𝑜𝑙𝑒 𝑆 6.022 𝑥 1023 𝑎𝑡𝑜𝑚𝑠 𝑂 16.3 𝑔 𝑆 𝑥 𝑥 32.06 𝑔 𝑆 1 𝑚𝑜𝑙𝑒 𝑆 = 3.061715533 𝑥 1023 𝑎𝑡𝑜𝑚𝑠 𝑆 = 3.06 𝑥 1023 𝑎𝑡𝑜𝑚𝑠 𝑆  1 𝑚𝑜𝑙𝑒 𝐶𝐻4 6.022 𝑥 1023 𝑚𝑜𝑙𝑒𝑐𝑢𝑙𝑒𝑠 𝐶𝐻4 6.07 𝑔 𝐶𝐻4 𝑥 𝑥 16.05 𝑔 𝐶𝐻4 1 𝑚𝑜𝑙𝑒 𝐶𝐻4 = 2.277479128 𝑥 1023 𝑚𝑜𝑙𝑒𝑐𝑢𝑙𝑒𝑠 𝐶𝐻4 = 2.28 𝑥 1023 𝑚𝑜𝑙𝑒𝑐𝑢𝑙𝑒𝑠 𝐶𝐻4  1 𝑚𝑜𝑙𝑒 𝐻𝑒 6.022 𝑥 1023 𝑎𝑡𝑜𝑚𝑠 𝐻𝑒 6.46 𝑔 𝐻𝑒 𝑥 𝑥 4.00 𝑔 𝐻𝑒 1 𝑚𝑜𝑙𝑒 𝐻𝑒 = 9.72553 𝑥 1023 𝑎𝑡𝑜𝑚𝑠 𝐻𝑒 = 9.73 𝑥 1023 𝑎𝑡𝑜𝑚𝑠 𝐻𝑒  Mass – MOLE RELATIONSHIP STOICHIOMETRIC CALCULATIONS MOLAR MASS ALLOWS THE CONVERSION OF MASS TO MOLE  Mass – MOLE RELATIONSHIP PERCENT COMPOSITION The following equation can determine the percentage composition of an element in the mass of the compound: (number of atoms)(atomic mass) % Element = × 100 (molar mass)  Mass – MOLE RELATIONSHIP (number of atoms)(atomic mass) PERCENT COMPOSITION % Element = × 100 (molar mass) Ethane (C2H6): What is the percentage composition of Carbon and Hydrogen? (MM C2H6 = 30.08 g/mole) 𝑔 2 𝑥 (12.01 ) %𝐶 = 𝑚𝑜𝑙𝑒 𝑥 100 = 79.85% 𝐶 𝑔 30.08 𝑚𝑜𝑙𝑒 𝑔 6 𝑥 (1.01 ) %𝐻 = 𝑚𝑜𝑙𝑒 𝑥 100 = 20.15% 𝐻 𝑔 30.08 𝑚𝑜𝑙𝑒  Mass – MOLE RELATIONSHIP Calculate the percentage composition of carbon, hydrogen, and oxygen in Vitamin E (C29H50O2). (MM C29H50O2 = 430.79 g/mole) 𝑔 29 𝑥 (12.01 ) %𝐶 = 𝑚𝑜𝑙𝑒 𝑥 100 = 80.85% 𝐶 𝑔 430.79 𝑚𝑜𝑙𝑒 𝑔 50 𝑥 (1.01 ) %𝐻 = 𝑚𝑜𝑙𝑒 𝑥 100 = 11.72% 𝐻 𝑔 430.79 𝑚𝑜𝑙𝑒 𝑔 2 𝑥 (16.00 ) %𝐶 = 𝑚𝑜𝑙𝑒 𝑥 100 = 7.43% 𝑂 𝑔 430.79 𝑚𝑜𝑙𝑒  Mass – MOLE RELATIONSHIP Magnesium hydroxide, Mg(OH)2 or also known as milk of magnesia is used as an antacid or laxative. How many percent of magnesium, oxygen, and hydrogen is present? (MM Mg(OH)2 = 58.33 g/mole) 𝑔 1 𝑥 (24.31 ) % 𝑀𝑔 = 𝑚𝑜𝑙𝑒 𝑥 100 = 41.68% 𝑀𝑔 𝑔 58.33 𝑚𝑜𝑙𝑒 𝑔 2 𝑥 (16.00 ) %𝑂 = 𝑚𝑜𝑙𝑒 𝑥 100 = 54.86% 𝑂 𝑔 58.33 𝑚𝑜𝑙𝑒 𝑔 2 𝑥 (1.01 ) %𝐻 = 𝑚𝑜𝑙𝑒 𝑥 100 = 3.46% 𝐻 𝑔 58.33 𝑚𝑜𝑙𝑒  Mass – MOLE RELATIONSHIP Cyclopropane, C3H6, is an anesthetic given by inhalation. Find the percent composition of carbon and hydrogen in cyclopropane. (MM C3H6 = 42.09 g/mole) 𝑔 3 𝑥 (12.01 ) %𝐶 = 𝑚𝑜𝑙𝑒 𝑥 100 = 85.60% 𝐶 𝑔 42.09 𝑚𝑜𝑙𝑒 𝑔 6 𝑥 (1.01 ) %𝐻 = 𝑚𝑜𝑙𝑒 𝑥 100 = 14.40% 𝐻 𝑔 42.09 𝑚𝑜𝑙𝑒  Mass – MOLE RELATIONSHIP Calculate the percentage composition of each element present in aluminum hydroxide, a gastric antacid. (MM Al(OH)3 = 78.01 g/mole) 𝑔 1 𝑥 (26.98 ) % 𝐴𝑙 = 𝑚𝑜𝑙𝑒 𝑥 100 = 34.59% 𝐴𝑙 𝑔 78.01 𝑚𝑜𝑙𝑒 𝑔 3 𝑥 (16.00 ) %𝑂 = 𝑚𝑜𝑙𝑒 𝑥 100 = 61.53% 𝑂 𝑔 78.01 𝑚𝑜𝑙𝑒 𝑔 3 𝑥 (1.01 ) %𝐻 = 𝑚𝑜𝑙𝑒 𝑥 100 = 3.88% 𝐻 𝑔 78.01 𝑚𝑜𝑙𝑒