Problems 4.1-4.7

Butane, C4H10 is a common fuel for heating rural homes in areas not serviced by natural gas sources. The equation for its combustion is:

2 C4H10 + 13 O2 -----> 8 CO2 + 10 H2O.

4.1. How many moles of oxygen are required to burn 3.4 moles of butane?

4.2. How many moles of carbon dioxide will be produced in the burning of 4.68 moles of butane?

4.3. How many moles of water will be produced along with 0.568 mole of carbon dioxide?

4.4. How many grams of butane can be burned by 1.42 moles of oxygen?

4.5. 9.43 grams of oxygen are used in burning butane. How many moles of water result?

4.6. Calculate the number of grams of carbon dioxide that will be produced by the burning of 78.4 grams of butane.

4.7. How many grams of oxygen are used in a reaction that produces 43.8 grams of water?


4.8. A reaction that produces great heat for welding and incendiary bombs is the "thermit" reaction: Fe2O3 + 2 Al -----> Al2O3 + 2 Fe. How many grams of Fe2O3 can be converted to aluminum oxide by the reaction of 47.1 grams of aluminum?

4.10. A common type of fire extinguisher depends upon the reaction of sodium hydrogen carbonate, NaHCO3, with sulfuric acid to produce carbon dioxide that develops a pressure to squirt water or foam onto a fire. The equation is 2 NaHCO3+ H2SO4 -------> Na2SO4 + 2 H2O + 2 CO2. If a fire extinguisher were designed to hold 600 grams of sodium hydrogen carbonate, how many grams of sulfuric would be required to react with all of it?

4.11. One of the methods for manufacturing sodium sulfate, widely used in making the kraft paper for grocery bags, involves the reaction 4 NaCl + 2 SO2 + 2 H2O + O2 -----> 2 Na2SO4 + 4 HCl. Calculate the number of grams of NaCl required to produce 5.00 kilograms of sodium sulfate.

4.12. 45.0 grams of zinc and 28.0 grams of sulfur are intimately mixed and caused to react until one is completely consumed. How many grams of zinc sulfide will be formed? How many grams of which element will remain unreacted?

4.13. A solution containing 1.46 grams of barium chloride is added to a solution containing 2.14 grams of sodium chromate, Na2CrO4. Find the number of grams of barium chromate that precipitate. Determine also which reactant was in excess, as well as the number of grams over the amount required by the limiting species.

The first step in the Ostwald process for manufacturing nitric acid involves the reaction between ammonia and oxygen described by the equation 4 NH3 -----> 4 NO + 6 H2O.

4.19. How many moles of ammonia will react with 49.6 moles of oxygen?

4.20. How many moles of NO will result from the reaction of 9.45 moles of ammonia?

4.21. If 10.3 moles of water are produced, how many moles of NO will also be produced?

4.22. How many moles of ammonia can be oxidized by 303 grams of oxygen?

4.23. If the reaction consumes 37.8 moles of ammonia, how many grams of water will be produced?

4.24. How many grams of ammonia are required to produce 307 grams of NO?

4.25. If 7.05 grams of water result from the reaction, what will be the yield of NO?

4.26. The reaction of a dry cell may be represented by Zn + 2 NH4Cl ------> ZnCl2 + 2 NH3 + H2. Calculate the number of grams of zinc consumed during the release of 9.32 grams of ammonia in such a cell.

4.27. The explosion of nitroglycerine is described by the equation 4 C3H3(NO3)3 -----> 12 CO2 + 10 H2O + 6 N2 + O2 How many grams of carbon dioxide are produced by the explosion of 69.7 grams of nitroglycerine?

4.29. One way of making sodium thiosulfate, the "hypo" in photographic developing, is described by the equation Na2CO3 + 2 Na2S + 4 SO2 ~~ 3 Na2S2O3 + CO2. How many grams of sodium carbonate are required to produce 494 grams of sodium thiosulfate?

4.30. 4.62 grams of oxygen and 2.98 grams of carbon monoxide are placed in a closed reaction vessel and the mixture is ignited. Combustion occurs until one of the gases is totally consumed. Calculate the grams of carbon dioxide produced. Identify the reactant that is in excess, and determine the number of unreacted grams that remain.

4.31. 2.71 grams of sodium iodide are dissolved in water, and the solution is added to a second solution containing 4.47 grams of lead(II) nitrate. Find the number of grams of lead(II) iodide that will precipitate, which compound was in excess, and by how many grams.

4.14. Copper is extracted from chalcocite, a copper(I) sulfide ore, by a reaction with oxygen that may be represented by the equation Cu2S + O2 ------> 2 Cu + SO2. If treatment of 41.9 grams of pure Cu2S by the process yields 29.2 grams of copper, calculate the percentage yield .

Section 4.6.

4.16. The discovery of oxygen occurred from the decomposition of mercury(II) oxide: 2 HgO -----> 2 Hg + O. What volume of oxygen would be produced by the reaction of 28.9 grams of the oxide, the gas being measured at STP?

4.17. How many liters of oxygen, measured at STP, are required for the complete combustion of 72.0 grams of heptane, C7H16; a component of gasoline? If air is 21'7. oxygen by volume, how many liters of air are necessary for this amount of fuel? (Note: CO2 and H2O are the only products.)

4.18. When nitric oxide, NO, is released in air it immediately combines with oxygen to produce nitrogen dioxide, NO2. If 0.345 liter of NO, measured at STP, react, how many liters of NO2, also measured at STP, will be formed?

4.33. In the Deacon process for manufacturing chlorine, a dry mixture of hydrogen chloride and air is passed over a heated catalyst. Oxidation occurs by the following reaction: 4 HCI + O2 -----> 2 Cl2 + 2 H2O. If the conversion is 58%, complete, how many tons of chlorine can be recovered from 1.4 tons of HCI?

4.34. Calculate the number of grams of HCI that must react with limestone, CaCO3, in order to liberate 650 ml of CO2, measured at STP. The equation is 2 HCI + CaCl2 + CO2 + H20.

4.35. The conventional laboratory method for preparing oxygen is to heat potassium chlorate, KClO3, in the presence of a catalyst. The oxygen is driven off, leaving a residue of potassium chloride. How many milliliters of the gas, measured at STP, will result from the decomposition of 2.06 grams of KClO3?

 

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