2006-09-23 18:41:21 · 6 answers · asked by churva 1 in Science & Mathematics ➔ Engineering
Ethanol boils at 78C, water at 100.
2006-09-23 18:47:36 · answer #1 · answered by zee_prime 6 · 0⤊ 4⤋
Relative Volatility
2016-10-06 11:08:31 · answer #2 · answered by ? 4 · 0⤊ 0⤋
The relative volatility depends on the composition of the liquid phase, basically. The following figures show the calculation for two compositions, namely ethanol 20-water 80 (mol %) and ethanol 80-water 20:
EtOH 20-H2O 80: (rel. volatility) = (.60/.20)/(.40/.80) = 6.00
EtOH 80-H2O 20: (rel. volatility) = (.88/.80)/(.12/.20) = 1.83
These figures take place at the bubble point temperature of each composition.
I calculated these values based on an NRTL model of the ethanol-water system's vapor-liquid equilibrium. Refer to the link below for the NRTL parameters used.
Send me an e-mail if you'd like me to help you out.
2006-09-23 19:43:44 · answer #3 · answered by Illusional Self 6 · 5⤊ 0⤋
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I hate to use this evil word, but you have to use Thermodynamics. IIRC, the alpha value is k_heavykey / k_lightkey. Thus, you need the k values for top and bottom. The k values will depend on temperature and composition. Recall from thermo that for an ideal solution k_i = y_i / x_i = P_i_sat / P, where y = vapor phase mole fraction and x = liquid phase mole fraction. So, if you know the total pressure and the vapor pressure at the temperature, you should be able to calculate the alpha values. If you use a more complicated solution model, you'll include the fugacity (yes, evil word) as well.
2016-04-02 06:10:42 · answer #4 · answered by ? 4 · 0⤊ 0⤋
ethanol is more volatile, freezes and boils at lower temperatures. If you light it in the palm of your hand, it'll feel colder because it accelerates the evaporation, subsequently pulling heat from your skin to keep up.
2006-09-23 18:56:11 · answer #5 · answered by ERIC G 3 · 0⤊ 1⤋
none
2006-09-23 20:55:51 · answer #6 · answered by delta s 4 · 0⤊ 1⤋