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Lab 1 - Moles, Mass, and Volume

# Lab 1 - Moles, Mass, and Volume - Lab 1 M oles M ass and...

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4/15/13 Lab 1 - Moles, Mass, and Volume www.webassign.net/ebooks/wsugencheml1/lab_1/manual.html 1/5 Contents > Lab 1 - Moles, Mass, and Volume Lab 1 - Moles, Mass, and Volume Purpose A To determine how many years it would take to count a mole of popcorn. B To determine the mass of a mole of popcorn, the mass of a mole of marbles, and the ratio of these molar masses. C To determine the volume of an individual water molecule, the volume of a marble, and the ratio of these volumes. Goals To gain an understanding of the mole and Avogadro's number. To gain an understanding of the molar mass and the density of a substance. To learn how to use the factor label method for solving mathematical problems. Introduction Atoms are extremely small. How small? Consider aluminum, a substance familiar to you. You know it as furniture (lawn chairs), pie pans, soft drink cans, and foil. However, one atom of aluminum has a mass of 4.5 × 10 -23 g. There are about 3.3 × 10 23 atoms of aluminum in a soft drink can. How do we count atoms and work with them when they are so incredibly small? We group them. Just as we often work with a dozen (12) items such as eggs, we work with moles of atoms. A mole is 6.02 × 10 23 of anything . It is a huge number. A mole of reams of copier paper (each 1.9 inches thick) stacked up would be 1.8 × 10 19 miles high, about 1/10 of the diameter of the Milky Way galaxy. It's only 9.2 × 10 7 miles from the earth to the sun. A mole of pennies is more money than the US government spent in the 20 th century. The number 6.02 × 10 23 is Avogadro's number. This honors Amedeo Avogadro, who recognized that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules. Since we have an extremely large number, the mole, and these infinitesimal particles, atoms, a mole of atoms is a convenient quantity to work with in a laboratory. A mole of helium atoms has a mass of 4 grams (a bit more than a peanut) and a mole of lead atoms has a mass of 207 grams (about the mass of a coffee mug). The mass of a mole of atoms of any element is called its molar mass . It

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4/15/13 Lab 1 - Moles, Mass, and Volume www.webassign.net/ebooks/wsugencheml1/lab_1/manual.html 2/5 has units of grams per mole (g/mol). The molar mass of atoms of each element is characteristic of that element and is listed on the periodic table. So far, we have talked about moles of atoms, which applies to elements.
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