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Unformatted text preview: Name: ___________________________________ CH101 Atomic Mass and Molar Mass – Study Guide sections 2.8 and 2.9 in the textbook Atomic Mass (Section 2.8) The atomic mass is listed __________________ each element’s symbol on the periodic table. This represents the average mass of the isotopes weighted according to _________________________________________________________________________________________. Practice Problem: Calculate the atomic mass for boron (B) given the following information. Isotope Mass Abundance 10 10.013 amu 19.78% 11 11.009 amu 80.22% B B Molar Mass (Section 2.9) Avogadro’s number = 1 mole = _____________________________ particles This number can be used as a conversion factor to convert between moles and particles (atoms, ions, molecules). Write the two possible conversion factors using Avogadro’s number: Molar Mass is the mass of _____________________________________________. The value of an element’s molar mass is numerically equal to ______________________________________________. For example, the molar mass of sodium can be obtained from the periodic table: 22.99 g/mol. Molar mass values can be turned into conversion factors that convert between mass in grams and moles. Write the two possible conversion factors that can be obtained from the molar mass for oxygen. Watch video tutorial on Blackboard Now solve the following problems using dimensional analysis: 1. Calculate the number of moles of iron in a 15.0 g sample of iron. (ans: 0.269 mol) 2. Calculate the number of atoms in 0.25 mol of silicon. (ans: 1.5 x 1023 atoms) 3. Calculate the mass in grams needed to have 2.65 x 1022 atoms of calcium. (ans: 1.76 g Ca) 2 End of Chapter Practice Problems Tro First Edition: #77, 79, 81, 85, 87 Tro Second Edition: #75, 79, 81, 85, 87 answers are located in Appendix III of the textbook Take the Quiz on Blackboard 3 ...
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This note was uploaded on 11/11/2011 for the course MATH 180 taught by Professor Byrns during the Spring '11 term at Montgomery College.
- Spring '11