Mole / Stoichiometry Calculations www.njctl.org Slide 3 / 157 - PDF document

Slide 1 / 157 New Jersey Center for Teaching and Learning Progressive Science Initiative This material is made freely available at www.njctl.org and is intended for the non-commercial use of students and teachers. These materials may not be used for any commercial purpose without the written permission of the owners. NJCTL maintains its website for the convenience of teachers who wish to make their work available to other teachers, participate in a virtual professional learning community, and/or provide access to course materials to parents, students and others. Click to go to website: www.njctl.org Slide 2 / 157 Mole / Stoichiometry Calculations www.njctl.org Slide 3 / 157 Table of Contents Click on the topic to go to that section · Avagadro's Number · Molar Mass · Molar Volume · Percent Composition · Emperical Formula

Slide 4 / 157 Avogadro's Number Return to Table of Contents Slide 5 / 157 Moles Recall an atom's atomic mass is equal to the number of protons plus the number of neutrons in the atom. Atomic Number 6 or number of protons (Z) C 12.01 Atomic Mass in amu The unit for atomic mass is amu. Carbon-12 has 6 protons and 6 neutrons. One amu is equal to 1/12 the mass of carbon-12 or approximately the mass of one proton or neutron mass of 1 proton = 1 amu Slide 6 / 157 Moles What if you wanted to measure the mass of one atom in the laboratory? Would it be possible? A single atom has a very small mass. One carbon atom has a mass of about 2.0 x 10 -23 grams .

Slide 7 / 157 The Mole It takes a lot of atoms to give us enough material to directly measure in a lab. Hydrogen has a mass of 1 amu. How many atoms of hydrogen would be needed to make a 1 gram sample of hydrogen? 602,200,000,000,000,000,000,000 The amount 6.02x10 23 is called Avogadro's number or a mole . How big is a mole? Slide 8 / 157 Calculating Avogadro's Number The atomic mass of one carbon atom is 12.01 amu or 2x10 -23 g. How many carbon atoms would it take to get 12.01 grams of carbon? Givens: mass of 1 carbon atom = 2x10 -23 g total mass of carbon atoms = 12.01 g 2x10 -23 g x ? of atoms = 12.01 g 12.01 g ? of atoms = 2x10 -23 g ? of atoms = 6.02 x 10 23 atoms Slide 9 / 157 Holy Mole-y! 1 mole of pennies could One mole of marbles would cover the entire Earth (oceans included) for a be distributed to all the depth of two miles! currently-living people of the world so that they could spend a million dollars per hour every hour (day and night) for the rest of their lives! If you were able to count at the rate of 1 million numbers a second, it would take about 20 billion years to count out one mole!

Slide 10 / 157 The Mole A mole is just a grouping of numbers...like dozen, ream, etc. A dozen means 12 of something. A mole means 6.02 x 10 23 of something. Common Grouping Quantities 1 dozen = 12 1 gross =144 1 ream = 500 1 mole = 6.02 x 10 23 Slide 11 / 157 1 How many eggs are in two dozen eggs? A 12 B 24 C 0.0833 D 2 E 6.02 x 10 23 Slide 11 (Answer) / 157 1 How many eggs are in two dozen eggs? A 12 24 B C 0.0833 D 2 6.02 x 10 23 E Answer B [This object is a pull tab]

Slide 12 / 157 How many eggs are in half a dozen eggs? 2 12 A B 24 C 6 D 0.5 6.02 x 10 23 E Slide 12 (Answer) / 157 2 How many eggs are in half a dozen eggs? 12 A 24 B C 6 D Answer 0.5 C 6.02 x 10 23 E [This object is a pull tab] Slide 13 / 157 3 How many particles of sand are in 0.5 moles of sand? A 1.5 x 10 23 B 3.01 x 10 23 C 6.02 x 10 23 D 1.2 x 10 24 E 6.02 x 10 24 1 mole = 6.02 x 10 23

Slide 13 (Answer) / 157 3 How many particles of sand are in 0.5 moles of sand? 1.5 x 10 23 A B 3.01 x 10 23 C 6.02 x 10 23 Answer D 1.2 x 10 24 B E 6.02 x 10 24 1 mole = 6.02 x 10 23 [This object is a pull tab] Slide 14 / 157 4 How many pieces of gold dust are in 2 moles of gold dust? A 1.5 x 10 23 B 3.01 x 10 23 C 6.02 x 10 23 D 1.2 x 10 24 E 6.02 x 10 24 1 mole = 6.02 x 10 23 Slide 14 (Answer) / 157 4 How many pieces of gold dust are in 2 moles of gold dust? A 1.5 x 10 23 B 3.01 x 10 23 C 6.02 x 10 23 D 1.2 x 10 24 Answer E 6.02 x 10 24 D 1 mole = 6.02 x 10 23 [This object is a pull tab]

Slide 15 / 157 5 How many dozen eggs are in a container of 6 eggs? A 4 B 0.5 C 1 D 2 6.02 x 10 23 E Slide 15 (Answer) / 157 5 How many dozen eggs are in a container of 6 eggs? A 4 B 0.5 C 1 Answer D 2 C 6.02 x 10 23 E [This object is a pull tab] Slide 16 / 157 6 How many dozen eggs are in a container of 18 eggs? 1.5 A B 3 C 0.67 D 2 6.02 x 10 23 E

Slide 16 (Answer) / 157 6 How many dozen eggs are in a container of 18 eggs? 1.5 A B 3 C 0.67 Answer D 2 A 6.02 x 10 23 E [This object is a pull tab] Slide 17 / 157 7 The Milky Way Galaxy may have up to 400 billion (4 x 10 14 stars). How many moles of stars does it have? A 1.5 x 10 9 B 6.7 x 10 -10 C 10 D 0.5 6.02 x 10 23 E 1 mole = 6.02 x 10 23 Slide 17 (Answer) / 157 7 The Milky Way Galaxy may have up to 400 billion (4 x 10 14 stars). How many moles of stars does it have? 1.5 x 10 A 9 B 6.7 x 10 -10 C 10 Answer A D 0.5 E 6.02 x 10 23 1 mole = 6.02 x 10 23 [This object is a pull tab]

Slide 18 / 157 8 Mathematicians estimate Earth's beaches contain nearly 5.6 x 10 21 grains of sand. How many moles of sand are on Earth's beaches? 1.5 A B 9.3 x 10 -3 C 10 D 107.5 6.02 x 10 23 E 1 mole = 6.02 x 10 23 Slide 18 (Answer) / 157 8 Mathematicians estimate Earth's beaches contain nearly 5.6 x 10 21 grains of sand. How many moles of sand are on Earth's beaches? 1.5 A B 9.3 x 10 -3 Answer C 10 D D 107.5 6.02 x 10 23 E 1 mole = 6.02 x 10 23 [This object is a pull tab] Slide 19 / 157 Measuring Matter with Moles The mole is the SI unit for measuring the amount of particles in a chemical substance. 1 mole of Carbon

Slide 20 / 157 Measuring Matter with Moles One mole (mol) of a substance is 6.02 x 10 23 representative particles of that substance. N n = Where: N A n is the number of moles N is the total number of particles N A is Avogadro's Number 6.02 x 10 23 Slide 21 / 157 Measuring Matter with Moles N A = 6.02 x10 23 atoms How many moles of Gold are there in a sample containing 3.01 x 10 23 atoms of Gold? Slide 22 / 157 9 How many atoms of titanium are in a sample containing 0.5 mole of titanium? A 1.5 x 10 23 N n = B 3.01 x 10 23 N A N A = 6.02 x 10 23 C 6.02 x 10 23 D 1.2 x 10 24 E 6.02 x 10 24

Slide 22 (Answer) / 157 9 How many atoms of titanium are in a sample containing 0.5 mole of titanium? A 1.5 x 10 23 N n = B 3.01 x 10 23 N A N A = 6.02 x 10 23 C 6.02 x 10 23 Answer D 1.2 x 10 24 B E 6.02 x 10 24 [This object is a pull tab] Slide 23 / 157 10 How many atoms of sodium are in a sample containing 2.0 moles of sodium? A 1.5 x 10 23 N n = B 3.01 x 10 23 N A N A = 6.02 x 10 23 C 6.02 x 10 23 D 1.2 x 10 24 6.02 x 10 22 E Slide 23 (Answer) / 157 10 How many atoms of sodium are in a sample containing 2.0 moles of sodium? 1.5 x 10 23 A N n = B 3.01 x 10 23 N A N A = 6.02 x 10 23 C Answer 6.02 x 10 23 D D 1.2 x 10 24 6.02 x 10 22 E [This object is a pull tab]

Slide 24 / 157 11 How many moles of potassium are in a sample containing 3.01 x 10 23 atoms of potassium? 1.0 A N n = N A 2.0 B N A = 6.02 x 10 C 0.5 23 0.75 D 6.02 x 10 24 E Slide 24 (Answer) / 157 11 How many moles of potassium are in a sample containing 3.01 x 10 23 atoms of potassium? A 1.0 N n = N A B 2.0 N A = 6.02 x 10 C 0.5 23 D Answer 0.75 C 6.02 x 10 24 E [This object is a pull tab] Slide 25 / 157 12 How many moles of potassium are in a sample containing 1.2 x 10 24 atoms of potassium? A 0.25 mol N B 0.50 mol n = N A C 1.0 mol N A = 6.02 x 10 23 D 2.0 mol E 3.0 mol

Slide 25 (Answer) / 157 12 How many moles of potassium are in a sample containing 1.2 x 10 24 atoms of potassium? A 0.25 mol N B 0.50 mol n = N A C 1.0 mol N A = 6.02 x 10 23 D 2.0 mol Answer 3.0 mol E D [This object is a pull tab] Slide 26 / 157 13 How many moles of tungsten atoms are there in a sample containing 1.8 x 10 24 atoms of tungsten? A 0.33 mol N n = 0.50 mol B N A C 1.0 mol N A = 6.02 x 10 23 1.5 mol D E 3.0 mol Slide 26 (Answer) / 157 13 How many moles of tungsten atoms are there in a sample containing 1.8 x 10 24 atoms of tungsten? A 0.33 mol N n = B 0.50 mol N A C 1.0 mol N A = 6.02 x 10 23 Answer D 1.5 mol E E 3.0 mol [This object is a pull tab]

Slide 27 / 157 14 How many moles of silver are there in a pure sample containing 1.5 x 10 23 atoms of silver? A 0.10 mol N n = B 0.25 mol N A C 0.50 mol N A = 6.02 x 10 23 D 1.0 mol E 1.5 mol Slide 27 (Answer) / 157 14 How many moles of silver are there in a pure sample containing 1.5 x 10 23 atoms of silver? A 0.10 mol N n = 0.25 mol B N A C 0.50 mol N A = 6.02 x 10 23 D 1.0 mol Answer B E 1.5 mol [This object is a pull tab] Slide 28 / 157 15 How many atoms are there in 5.00 mol of hafnium? A 6.02 x10 23 atoms N B 1.20 x 10 23 atoms n = N A 1.20 x 10 22 atoms C N A = 6.02 x 10 23 D 3.43 x 10 23 atoms E 3.01 x 10 24 atoms