Moles and stoichiometry practice problems

# Moles and stoichiometry practice problems - Moles and...

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Moles and stoichiometry practice problems (from Chapter 3 in Brady, Russell, and Holum’s Chemistry, Matter and its Changes, 3 rd Ed. ) Concept of mole/molar ratio 1) 1) How many moles of sodium atoms correspond to 1.56x10 21 atoms of sodium? 2) 2) How many moles of Al atoms are needed to combine with 1.58 mol of O atoms to make aluminum oxide, Al 2 O 3 ? 3) 3) How many moles of Al are in 2.16 mol of Al 2 O 3 ? 4) 4) Aluminum sulfate, Al 2 (SO 4 ) 3 , is a compound used in sewage treatment plants. a. a. Construct a pair of conversion factors that relate moles of aluminum to moles of sulfur for this compound b. b. Construct a pair of conversion factors that relate moles of sulfur to moles of Al 2 (SO 4 ) 3 c. c. How many moles of Al are in a sample of this compound if the sample also contains 0.900 mol S? d. d. How many moles of S are in 1.16 mol Al 2 (SO 4 ) 3 ? 2) 5) How many moles of H 2 and N 2 can be formed by the decomposition of 0.145 mol of ammonia, NH 3 ? 3) 6) What is the total number of atoms in 0.260 mol of glucose, C 6 H 12 O 6 ? 4) 7) What is the mass of 1.00 mol of each of the following elements? a. a. Sodium b. b. Sulfur c. c. Chlorine 5) 8) Determine the mass in grams of each of the following: a. a. 1.35 mol Fe b. b. 24.5 mol O c. c. 0.876 mol Ca d. d. 1.25 mol Ca 3 (PO 4 ) 2 e. e. 0.625 mol Fe(NO 3 ) 3 f. f. 0.600 mol C 4 H 10 g. g. 1.45 mol (NH 4 ) 2 CO 3 6) 9) Calculate the number of moles of each compound: a. a. 21.5 g CaCO 3 b. b. 1.56 g NH 3 c. c. 16.8 g Sr(NO 3 ) 2 d. d. 6.98 μ g Na 2 CrO 4

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Percent composition and empirical formulas 7) 10) Calculate the percentage composition by mass of each element in the following compounds: a. a. NaH 2 PO 4 b. b. NH 4 H 2 PO 4 c. c. (CH 3 ) 2 CO 8) 11) Phencyclidine is C 17 H 25 N. A sample suspected of being this illicit drug was found to
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## This note was uploaded on 11/05/2011 for the course ECON 101 taught by Professor Graham during the Spring '08 term at N. Colorado.

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Moles and stoichiometry practice problems - Moles and...

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