Octane, heat of combustion

Oxygenate Blending octane, 1/2CRON + MON) " Heat of combustion, MJ/ ] Specific gravity Boiling point, °C... 

Again, it is convenient to follow the seven-step procedure to solve this problem. We are asked to find an enthalpy of formation. Because enthalpy is a state function, we can visualize the reaction as occurring through decomposition and formation reactions. Appendix D lists enthalpies of formation, and the experimental heat of combustion is provided. We can use Equation to relate the enthalpy of combustion to the standard enthalpy of formation for octane. 

The heat of combustion of hexane, C6H14(1), is —4163 kj-mol Use this fact and the values for the enthalpies of combustion of various organic compounds found in Table 6.3 to compare benzene, ethanol, hexane, and octane as possible fuels by doing the following, (a) Calculate the heat produced per gram of each of these substances, (b) From standard reference sources, find the density of each liquid and determine the heat produced per liter of liquid. 

Methyl ferf-butyl ether (MTBE), C5H12O, a gasoline additive used to boost octane ratings, has AH°f = —313.6 kj/mol. Write a balanced equation for its combustion reaction, and calculate its standard heat of combustion in kilojoules. 

A-14. Given the following heats of combustion (in kilojoules per mole) for the homologous series of unbranched alkanes hexane (4163), heptane (4817), octane (5471), nonane (6125), estimate the heat of combustion (in kilojoules per mole) for pentadecane. 

By comparing octane and oleic acid, you can see that the heat of combustion of fossil fuels must be similar to the heat of combustion of fats. 

One such rule (W. M. Thornton, 1917) is that the heat of combustion is about — 52.5n kcal. per mole, where n is the number of atoms of oxygen required to bum a molecule of the compound. Heats of combustion calculated in this manner are in satisfactory agreement with observation for hydrocarbons, e.g., octane (CsHi ) calculated, — 1312 kcal., observed,... 

Example 5.1 Determine the heat of combustion of n-octane at 620°C and 1 atm. The heats of formations of the various species and their heat capacities are given below. Data The standard heats of formation of the species (at 298 K) are... 

Compare the latent heat, heat of combustion, and octane number of ethanol with the values of methanol in Table 6.1. How does the price of ethanol in dollars per million Btu compare with the price of methanol What are the important methods of manufacture of ethanol Who are the five leading producers How many of these also produce methanol ... 

Octadecanoic acid, 737 Octane isomers, heats of combustion and relative stability, 75—76 Octane number of gasoline, 71 2-Octanol, 555... 

The problem asks for the energy produced by the combustion of 1 gallon of octane. A/f above has units of kJ/mol octane. We need to convert from kJ/mol octane to kJ/gallon octane. The heat of combustion for 1 gallon of octane is ... 

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