Ethanol specific heat

Figure 5.31 Concentration dependence of CD spectra at 205 nm (top) and specific heat (bottom) of DCg.gPC tubules prepared in ethanol-water (70 30) at lipid concentrations of (a) 0.2, (b) 0.5, (c) 1.0, (d) 2.0, and (e) 5.0 mg/ml. These results show crossover from continuous to discontinuous melting as lipid concentration is increased. Reprinted with permission from Ref. 137. Copyright 1997 by the American Chemical Society.

A sample of ethanol, C2H5OH, absorbs 23.4 kj of energy. The temperature of the sample increases from 5.6°C to 19.8°C. What is the mass of the ethanol sample The specific heat capacity of ethanol is 2.46 J/g °C. 

The specific heat is very close to the value for ethanol. 

A 1.000-gram sample of ethanol, C2H5OH, was burned in a bomb calorimeter whose heat capacity had been determined to be 2.71 kJ/°C. The temperature of 3000 grams of water rose from 24.284°C to 26.225°C. Determine A for the reaction in joules per gram of ethanol, and then in kilojoules per mole of ethanol. The specific heat of water is 4.184J/g-°C. The combustion reaction is... 

The amount of heat given off by the system (in the sealed compartment) raises the temperature of the calorimeter and its water. The amount of heat absorbed by the water can be calculated using the specific heat of water similarly, we use the heat capacity of the calorimeter to find the amount of heat absorbed by the calorimeter. The sum of these two amounts of heat is the total amount of heat released by the combustion of 1.000 gram of ethanol. We must then scale that result to correspond to one mole of ethanol. 

Monoclinic prismatic crystals from water or alcohol, mp 209.5. dj5 1.400. Eutectic with cyanamide at 35.6 (15% dicyanodiamide). Specific heat 0.456 at 0-204 . Neutral reaction. Soly in water at 13 2.26%, more sol in hot water. Solns above 80s dec slowly, yielding ammonia. Soly in abs ethanol at 13 1.26% in ether 0.01%. Insol in benzene, chloroform. Sol in liq ammonia. 

I, 4530. Specific heat at 20° about 0.62. Viscosity (Engler) at 20s about 6.08. Readily sol in ether, gasoline, petr ether, benzene, chloroform, oils. Slightly sol in methanol, ethanol, acetone, glacial acetic acid. Coned H,SO( at 70 is discolored, but the squalane remains unchanged. 

Ethanol has a specific heat of 2.44 J/(g °C). What does this mean ... 

The specific heat of water (4.2 kJ-kg -K ) is typically two to three times greater than the specific heat of other common liquids such as acetonitrile (2.23 kJ-kg -K ) or ethanol (2.44 kJ kg K ), even when the water molecule is much smaller, with fewer degrees of freedom. The large value of specific heat can be attributed to the existence of the local quasi-stable low-frequency oscillatory modes. Examples include hindered translation around 50 cm , intermolecular vibration around 200 cm and librational modes around 585 cm . In addition, HB breaking and re-formation also contribute to the specific heat as all of them contribute to fluctuation in the enthalpy. Note that... 

Table 6.31 Specific Heat of Aqueous Solutions of Ethanol (30)... 

Procedures for the extraction of carotenoids from a wide variety of tissues have been reported in the literature. Because of differences in plant materials, no one method can be considered universal. However, the various methods are quite similar in principle. Carotenoids are extracted with an organic solvent such as methanol, ethanol, acetone, hexane, or petroleum ether. These may be used singly or as mixtures of two or more. In some cases, heating has been used to facilitate the extraction, although there is some risk in this as noted above. Grinding or blending has been used with some tissues, and in some cases this has been carried out with the solvent directly. When extracting fresh tissue, the initial extraction must be carried out with a water-miscible solvent such as acetone, methanol, or ethanol. Specific examples of procedures for various tissues are discussed in the review by Davies (1976). 

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