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9.55 Hydrogen gas will react with either acetylene or ethylene gas. The thermochemical equations for these reactions are provided below. Write the thermochemical equation for the conversion of acetylene into ethylene by hydrogen gas.
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Chapter 9 Solutions
Chemistry for Engineering Students
- Hydrogen cyanide is used in the manufacture of clear plastics such as Lucite and Plexiglas. It is prepared from ammonia and natural gas (CH4). 2NH3(g)+3O2(g)+2CH4(g)2HCN(g)+6H2O(g) The reaction evolves 469 kJ of heat per mol of HCN formed. Is the reaction endothermic or exothermic? What is the value of q when 2 mol HCN forms?arrow_forwardGiven the following (hypothetical) thermochemical equations: A+B2C;H=447kJA+3D2E;H=484kJ2D+B2F;H=429kJ Calculate H, in kJ, for the equation 4E+5B4C+6Farrow_forwardThe process of dissolving ammonium nitrate, NH4NO3, in water is an endothermic process. What is the sign of q? If you were to add some ammonium nitrate to water in a flask, would you expect the flask to feel warm or cool?arrow_forward
- Give the definition of the standard enthalpy of formation for a substance. Write separate reactions for the formation of NaCl, H2O , C6H12O6, and PbSO4 that have H values equal to Hf for each compound.arrow_forwardHydrogen sulfide, H2S, is a foul-smelling gas. It burns to form sulfur dioxide. 2H2S(g)+3O2(g)2SO2(g)+2H2O(g);H=1036kJ Calculate the enthalpy change to burn 27.4 g of hydrogen sulfide.arrow_forwardHydrogen sulfide, H2S, is a poisonous gas with the odor of rotten eggs. The reaction for the formation of H2S from the elements is H2(g)+18S3(rhombic)H2S(g) Use Hesss law to obtain the enthalpy change for this reaction from the following enthalpy changes: H2S(g)+32O2(g)H2O(g)+SO2(g);H=518kJH2(g)+12O2(g)H2O(g);H=242kJ18S8(rhombic)+O2(g)SO2(g);H=297kJarrow_forward
- A typical fat in the body is glyceryl trioleate, C57H104O6. When it is metabolized in the body, it combines with oxygen to produce carbon dioxide, water, and 3.022104 kJ of heat per mole of fat. (a) Write a balanced thermochemical equation for the metabolism of fat. (b) How many kilojoules of energy must be evolved in the form of heat if you want to get rid of five pounds of this fat by combustion? (c) How many nutritional calories is this? (1 nutritional calories =1103 calories)arrow_forwardThe head of a strike anywhere match contains tetraphosphorus trisulfide, P4S3. In an experiment, a student burned this compound in an excess of oxygen and found that it evolved 3651 kJ of heat per mole of P4S3 at a constant pressure of 1 atm. She wrote the following thermochemical equation: P4S3(s)+8O2(g)P4O10(s)+3SO2(g);H=3651kJ Calculate the standard enthalpy of formation of P4S3, using this students result and the following standard enthalpies of formation: P4O10(s), 3009.9 kJ/mol; SO2(g), 296.8 kJ/mol. How does this value compare with the value given in Appendix C?arrow_forward9.103 One reason why the energy density of a fuel is important is that to move a vehicle one must also move its unburned fuel. Octane is a major component of gasoline. It burns according to the reaction 2C8H18(l)+25O2(g)16CO2(g)+18H2O(g) H = 1.10104 kJ Starting from this thermochemical equation, describe how you would determine the energy density, in kJ/g, for octane. Be sure to indicate what you would need to calculate or look up to complete this problem.arrow_forward
- Ammonium nitrate is an oxidizing agent and can give rise to explosive mixtures. A mixture of 2.00 mol of powdered aluminum and 3.00 mol of ammonium nitrate crystals reacts exothermically yielding nitrogen gas, water vapor, and aluminum oxide. How many grams of the mixture are required to provide 245 kJ of heat? See Appendix C for data.arrow_forwardEthylene glycol, HOCH2CH2OH, is used as antifreeze. It is produced from ethylene oxide, C2H4O, by the reaction C2H4O(g)+H2O(l)HOCH2CH2OH(l) Use Hesss law to obtain the enthalpy change for this reaction from the following enthalpy changes: 2C2H4O(g)+5O2(g)4CO2(g)+4H2O(l);H=2612.2kJHOCH2CH2OH(l)+52O2(g)2CO2(g)+3H2O(l);H=1189.8kJarrow_forwardSalicylic acid, C7H6O3, is one of the starting materials in the manufacture of aspirin. When 1.00 g of salicylic acid burns in a bomb calorimeter, the temperature of the bomb and water goes from 23.11C to 28.91C. The calorimeter and water absorb 21.9 kJ of heat. How much heat is given off when one mole of salicylic acid burns?arrow_forward
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