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## Chapter 11: The Mole

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**11.1 Measuring Matter**Roses and eggs are conveniently packaged as a dozen. Sheets of paper are packaged as a ream. Small item are packaged in large amounts to make life easier. The same is true for atoms. However, because atoms are really, really, really small, the amounts of them that are packaged together are really, really, really big**A package of atoms or compounds that chemists use is called**the Mole (from the Greek word for “pile”).**A package of atoms or compounds that chemists use is called**the Mole (from the Greek word for “pile”). A mole (abbreviated “mol”) contains 602,200,000,000,000,000,000,000 of anything. This really large number is often called Avogadro’s Number and is abbreviated 6.022 × 1023.**If you know the number of moles, then the amount of atoms or**molecules can be calculated. How many atoms are in 2 moles of Al? In a calculator, you would put in 2 × 6.022 EE 23. Pushing the button that says EE takes the place of the “ × 10” and is the way calculators are meant to be used.**How many molecules of HCl are in 3.57 moles of HCl?**In a calculator, you would put in 3.57 × 6.022 EE 23. When stating the answer don’t forget to include the “× 1024”.**The opposite can also be done.**How many moles is 9.03 × 1023 atoms of K?**Notice, in both cases you use that fact that 1 mol = 6.022**× 1023 (this is called a conversion factor). Whether the 6.022 × 1023 is on the top or bottom of the railroad tracks depends on what you start the problem with.**How would you set up the railroad tracks to find out how**many atoms is 2.9 moles of Fe? You do not need to calculate an answer.**How would you set up the railroad tracks to find out how**many atoms is 2.9 moles of Fe? You do not need to calculate an answer.**How would you set up the railroad tracks to find out how**many atoms is 2.9 moles of Fe? You do not need to calculate an answer.**How would you set up the railroad tracks to find out how**many atoms is 2.9 moles of Fe? You do not need to calculate an answer.**How would you set up the railroad tracks to find out how**many atoms is 2.9 moles of Fe? You do not need to calculate an answer.**How would you set up the railroad tracks to find out how**many atoms is 2.9 moles of Fe? You do not need to calculate an answer.**How would you set up the railroad tracks to find out how**many moles is 4.9 × 1023 molecules of Rb3P? You do not need to calculate an answer.**How would you set up the railroad tracks to find out how**many moles is 4.9 × 1023 molecules of Rb3P? You do not need to calculate an answer.**How would you set up the railroad tracks to find out how**many moles is 4.9 × 1023 molecules of Rb3P? You do not need to calculate an answer.**How would you set up the railroad tracks to find out how**many moles is 4.9 × 1023 molecules of Rb3P? You do not need to calculate an answer.**11.2 Masses and the Mole**The mole is not only handy to counting a large amount of atoms or molecules, it is even more useful when measuring out amounts of elements or compounds. The masses on the periodic table have been designed to be the amount of grams in a mole of that element.**For example, look at sulfur.**The information shown for sulfur tells us that 1 mol of sulfur = 32.066 grams of sulfur. Likewise, 2 mols of sulfur = 2 × 32.066 or 64.132 grams of sulfur, etc. This allows for amounts of elements to be easily measured in the laboratory and turned into moles.**A student measures out 12 g of Mg in lab. How many moles**does this student have?**A student measures out 12 g of Mg in lab. How many moles**does this student have? In the calculator you would put in 12 ÷ 24.31. Notice the conversion factor is unique for each element and must come from the periodic table.**The opposite can also be done.**A student needs 2.3 mols of B for an experiment. How many grams should this student measure out? In the calculator you would put in 2.3 × 10.8.**How would you set up the railroad tracks to find out how**many grams is 2.9 moles of Fe? You do not need to calculate an answer.**How would you set up the railroad tracks to find out how**many grams is 2.9 moles of Fe? You do not need to calculate an answer.**How would you set up the railroad tracks to find out how**many grams is 2.9 moles of Fe? You do not need to calculate an answer.**How would you set up the railroad tracks to find out how**many grams is 2.9 moles of Fe? You do not need to calculate an answer.**How would you set up the railroad tracks to find out how**many grams is 2.9 moles of Fe? You do not need to calculate an answer.**How would you set up the railroad tracks to find out how**many moles is 4.3 grams of P? You do not need to calculate an answer.**How would you set up the railroad tracks to find out how**many moles is 4.3 grams of P? You do not need to calculate an answer.**How would you set up the railroad tracks to find out how**many moles is 4.3 grams of P? You do not need to calculate an answer.**How would you set up the railroad tracks to find out how**many moles is 4.3 grams of P? You do not need to calculate an answer.**How would you set up the railroad tracks to find out how**many moles is 4.3 grams of P? You do not need to calculate an answer.**Sections 11.1 and 11.2 can be put together into one big**calculation.**A student needs 2.6 × 1023 atoms of fluorine for an**experiment. How many grams of fluorine should the student measure out? In the calculator you would put in 2.6 EE 23 ÷ 6.022 EE 23 × 19.**Moles will always be in the middle of these kinds of**calculations!**The opposite can also be done.**A student has 56.7 grams of aluminum. How many atoms of aluminum does the student have? In the calculator you would put in 56.7 ÷ 27.0 × 6.022 EE 23.**How would you set up railroad tracks to calculate how many**grams of Rb are 9.4 × 1023 atoms of Rb? You do not need to calculate and answer.**How would you set up railroad tracks to calculate how many**grams of Rb are 9.4 × 1023 atoms of Rb? You do not need to calculate and answer.**How would you set up railroad tracks to calculate how many**grams of Rb are 9.4 × 1023 atoms of Rb? You do not need to calculate and answer.**How would you set up railroad tracks to calculate how many**grams of Rb are 9.4 × 1023 atoms of Rb? You do not need to calculate and answer.**How would you set up railroad tracks to calculate how many**grams of Rb are 9.4 × 1023 atoms of Rb? You do not need to calculate and answer.**How would you set up railroad tracks to calculate how many**grams of Rb are 9.4 × 1023 atoms of Rb? You do not need to calculate and answer.