문제 54b
Determine the empirical and molecular formulas of each of the following substances: (b) Cadaverine, a foul-smelling substance produced by the action of bacteria on meat, contains 58.55% C, 13.81% H, and 27.40% N by mass; its molar mass is 102.2 g/mol.
문제 54c
Determine the empirical and molecular formulas of each of the following substances: (c) Epinephrine (adrenaline), a hormone secreted into the bloodstream in times of danger or stress, contains 59.0% C, 7.1% H, 26.2% O, and 7.7% N by mass; its molar mass is about 180 u.
문제 55a
(a) Combustion analysis of toluene, a common organic solvent, gives 5.86 mg of CO2 and 1.37 mg of H2O. If the compound contains only carbon and hydrogen, what is its empirical formula?
문제 55b2
(b) Menthol, the substance we can smell in mentholated cough drops, is composed of C, H, and O. A 0.1005-g sample of menthol is combusted, producing 0.2829 g of CO2 and 0.1159 g of H2O. What is the empirical formula for menthol? If menthol has a molar mass of 156 g/mol, what is its molecular formula?
문제 56a
(a) The characteristic odor of pineapple is due to ethyl butyrate, a compound containing carbon, hydrogen, and oxygen. Combustion of 2.78 mg of ethyl butyrate produces 6.32 mg of CO2 and 2.58 mg of H2O. What is the empirical formula of the compound?
문제 56b
(b) Nicotine, a component of tobacco, is composed of C, H, and N. A 5.250-mg sample of nicotine was combusted, producing 14.242 mg of CO2 and 4.083 mg of H2O. What is the empirical formula for nicotine? If nicotine has a molar mass of 160 ± 5 g/mol, what is its molecular formula?
문제 57a
Valproic acid, used to treat seizures and bipolar disorder, is composed of C, H, and O. A 0.165-g sample is combusted to produce 0.166 g of water and 0.403 g of carbon dioxide. What is the empirical formula for valproic acid?
문제 58a
Propenoic acid, C3H4O2, is a reactive organic liquid that is used in the manufacturing of plastics, coatings, and adhesives. An unlabeled container is thought to contain this liquid. A 0.275-g sample of the liquid is combusted to produce 0.102 g of water and 0.374 g carbon dioxide. Is the unknown liquid propenoic acid? Support your reasoning with calculations.
문제 59
Washing soda, a compound used to prepare hard water for washing laundry, is a hydrate, which means that a certain number of water molecules are included in the solid structure. Its formula can be written as Na2CO3 # xH2O, where x is the number of moles of H2O per mole of Na2CO3. When a 2.558-g sample of washing soda is heated at 125 C, all the water of hydration is lost, leaving 0.948 g of Na2CO3. What is the value of x?
문제 60
Epsom salts, a strong laxative used in veterinary medicine, is a hydrate, which means that a certain number of water molecules are included in the solid structure. The formula for Epsom salts can be written as MgSO4 # xH2O, where x indicates the number of moles of H2O per mole of MgSO4. When 5.061 g of this hydrate is heated to 250 C, all the water of hydration is lost, leaving 2.472 g of MgSO4. What is the value of x?
문제 61
Hydrofluoric acid, HF(aq), cannot be stored in glass bottles because compounds called silicates in the glass are attacked by the HF(aq). Sodium silicate (Na2SiO3), for example, reacts as follows: Na2SiO3(s) + 8 HF(aq) → H2SiF6(aq) + 2 NaF(aq) + 3 H2O(l) (a) How many moles of HF are needed to react with 0.300 mol of Na2SiO3? (b) How many grams of NaF form when 0.500 mol of HF reacts with excess Na2SiO3? (c) How many grams of Na2SiO3 can react with 0.800 g of HF?
문제 62a
The reaction between potassium superoxide, KO2, and CO2, 4 KO2 + 2 CO2¡2K2CO3 + 3 O2 is used as a source of O2 and absorber of CO2 in selfcontained breathing equipment used by rescue workers. (a) How many moles of O2 are produced when 0.400 mol of KO2 reacts in this fashion?
문제 62b
The reaction between potassium superoxide, KO2, and CO2, 4 KO2 + 2 CO2¡2K2CO3 + 3 O2 is used as a source of O2 and absorber of CO2 in selfcontained breathing equipment used by rescue workers. (b) How many grams of KO2 are needed to form 7.50 g of O2?
문제 63b,c
Several brands of antacids use Al1OH23 to react with stomach acid, which contains primarily HCl: Al(OH)3(s) + HCl(aq) → AlCl3(aq) + H2O(l) (b) Calculate the number of grams of HCl that can react with 0.500 g of Al(OH)3. (c) Calculate the number of grams of AlCl3 and the number of grams of H2O formed when 0.500 g of Al(OH)3 reacts.
문제 64b,c
An iron ore sample contains Fe2O3 together with other substances. Reaction of the ore with CO produces iron metal: Fe2O3(s) + CO(g) → Fe(s) + CO2(g) (b) Calculate the number of grams of CO that can react with 0.350 kg of Fe2O3. (c) Calculate the number of grams of Fe and the number of grams of CO2 formed when 0.350 kg of Fe2O3 reacts.
문제 65b
Aluminum sulfide reacts with water to form aluminum hydroxide and hydrogen sulfide. (a) Write the balanced chemical equation for this reaction. (b) How many grams of aluminum hydroxide are obtained from 14.2 g of aluminum sulfide?
문제 66a
Calcium hydride reacts with water to form calcium hydroxide and hydrogen gas. (a) Write a balanced chemical equation for the reaction.
문제 66b
Calcium hydride reacts with water to form calcium hydroxide and hydrogen gas. (b) How many grams of calcium hydride are needed to form 4.500 g of hydrogen?
문제 67c
Automotive air bags inflate when sodium azide, NaN3, rapidly decomposes to its component elements: 2 NaN31s2¡2 Na1s2 + 3 N21g2 (c) How many grams of NaN3 are required to produce 10.0 ft3 of nitrogen gas, about the size of an automotive air bag, if the gas has a density of 1.25 g/L?
문제 68a
The complete combustion of octane, C8H18, a component of gasoline, proceeds as follows: 2 C8H18(l) + 25 O2(g) → 16 CO2(g) + 18 H2O(g) (a) How many moles of O2 are needed to burn 1.50 mol of C8H18?
문제 68b
The complete combustion of octane, C8H18, a component of gasoline, proceeds as follows: 2 C8H18(l) + 25 O2(g) → 16 CO2(g) + 18 H2O(g) (b) How many grams of O2 are needed to burn 10.0 g of C8H18?
문제 68c
The complete combustion of octane, C8H18, a component of gasoline, proceeds as follows: 2 C8H18 (l) + 25 O2 (g) → 16 CO2 (g) + 18 H2O (g) (c) Octane has a density of 0.692 g/mL at 20 °C. How many grams of O2 are required to burn 15.0 gal of C8H18 (the capacity of an average fuel tank)?
문제 68d
The complete combustion of octane, C8H18, a component of gasoline, proceeds as follows: 2 C8H18(l) + 25 O2(g) → 16 CO2(g) + 18 H2O(g). (d) How many grams of CO2 are produced when 15.0 gal of C8H18 are combusted? (d) How many grams of CO2 are produced when 15.0 gal of C8H18 are combusted?
문제 70
Detonation of nitroglycerin proceeds as follows: 4 C3H5N3O91l2¡ 12 CO21g2 + 6 N21g2 + O21g2 + 10 H2O1g2 (a) If a sample containing 2.00 mL of nitroglycerin 1density = 1.592 g>mL2 is detonated, how many moles of gas are produced?
- The complete combustion of octane, C8H18, produces 5470 kJ of heat. Calculate how many grams of octane are required to produce 20,000 kJ of heat.
문제 71
문제 72b
The combustion of one mole of liquid octane, CH3(CH2)6CH3, produces 5470 kJ of heat. Calculate how much heat is produced if 1.000 gallon of octane is combusted.
문제 73a
(a) Define the terms limiting reactant and excess reactant.
문제 73b
(b) Why are the amounts of products formed in a reaction determined only by the amount of the limiting reactant?
문제 73c
(c) Why should you base your choice of which compound is the limiting reactant on its number of initial moles, not on its initial mass in grams?
문제 74a
(a) Define the terms theoretical yield, actual yield, and percent yield.
Ch.3 - Chemical Reactions and Reaction Stoichiometry
