Answers Here are some additional practice problems for this lesson.  You can check the answers by clicking on the Answer link to the right.  (Use atomic weights that are precise to the hundredths place.) (Modified from Exercise 8) - Gram-mole Practice Problems 1. What is the weight of 0.30 mole of sulfur?  2. What is the weight of 5.5 mole of silicon?  3. How many moles are there in 45 g of Cl?  4. Change 34 g of lithium to moles.  5. What is the weight of 4.30 mole of sodium?  6. What is the weight of 1.75 mole of Ca?  7. How many moles are there in 85.3 g of P?  8. Change 0.566 g of silver to moles.    (Modified from Exercise 13) - Practice Calculating Formula Weights 1. HCl 2. SiH4 3. C3H6O2 4. Fe(NO3)3 5. NaCl 6. CaSO4 7. C2H4O2 8. Sn(CO3)2    (Modified from Exercise 14) - Gram-mole Practice Problems 1. Change 3.4 moles of HCl to grams.  2. Change 8.5 g of SiH4 to moles.  3. Change 5.20 moles of C3H6O2 to grams.  4. Change 13.2 g of Fe(NO3)3 to moles.  5. Change 3.4 moles of NaCl to grams.  6. Change 8.5 g of CaSO4 to moles.  7. Change 5.20 moles of C2H4O2 to grams.  8. Change 13.2 g of Sn(CO3)2 to moles.   (Modified from Exercise 17) - Practice Calculating Composition From Formula 1. SO2 2. Na2CO3 3. FeCO3 4. CH2O 5. CaCO3 6. Fe(OH)3    (Modified from Exercise 19) - Practice Determining Empirical Formulas 1. Calculate the empirical formula of the compound that contains 1.0 g S for each 1.5 g O. 2. Calculate the empirical formula of the compound containing 75.0% C and 25.0% H. 3. Calculate the empirical formula of the compound containing 81.8% C and 18.2% H. 4. Determine the empirical formula of the compound containing 37.5% C, 12.5% H, and 50.0% O by weight. 5. Determine the empirical formula of the compound containing 26.1% C, 4.3% H, and 69.6% O by weight. 6. Determine the empirical formula of the compound containing 38.7% C, 16.1% H, and 45.2% N by weight. 7. What is the empirical formula of a compound if a 50.0 g sample of it contains 9.1 g Na, 20.6 g Cr, and 22.2 g O?   (Modified from Exercise 21) - Practice Determining Molecular Formulas 1. Empirical formula C3H7, molecular weight 86 g/mole 2. Empirical formula S, molecular weight 256 g/mole 3. Empirical formula CH, molecular weight 26 g/mole 4. Empirical formula NO2, molecular weight 46 g/mole   Top of Page Back to Course Homepage E-mail instructor: Clackamas Community College ©1998, 2002 Clackamas Community College, Hal Bender