Boiling point of ethanol

A.l Classify the following properties as chemical or physical (a) objects made of silver become tarnished (b) the red color of rubies is due to the presence of chromium ions (c) the boiling point of ethanol is 78°C. 

The vapor pressure of ethanol at 34.9°C is 13.3 kPa. Use the data in Table 6.3 to estimate the normal boiling point of ethanol. 

Fig. 2.9 Microwave heating (single-mode reactor) of ethanol under open-vessel conditions. Initially, the temperature rises during the heating phase (AB), above the normal boiling point of ethanol (78 °C), to a point C at which the solvent bumps and starts to boil at the vapor/liquid interface. At this point, the...

Give reason for the higher boiling point of ethanol In comparison to methoxyme thane. 

An azeotrope is a mixture of two or more substances that boils at a constant temperature, either higher or lower than any of its constituents. Thus an 8.5 1 mole mixture of ethanol and water boils like a pure substance, distilling at 78.2°, which is lower than the boiling point of ethanol (78.5°) or of water (100°). In contrast, a 1.35 1 mole mixture of methanoic (formic) acid and water boils at 107.1°, which is higher than the boiling points of either methanoic acid (100.7°) or water (100°). 

Calculate the normal boiling point of ethanol (CH3CH2OH), given that its enthalpy of vaporization is 38.6 kj/mol and its entropy of vaporization is 110 J/(K mol). 

Hydrogen bonding has a large effect on the physical properties of organic compounds, as shown by the boiling points of ethanol (ethyl alcohol) and dimethyl ether, two isomers of molecular formula C2H60 ... 

Problem 9.7 Explain why dimethyl ether (0113)20 and ethanol (CH3CH2OH) are both water soluble, but the boiling point of ethanol (78 °C) is much higher than the boiling point of dimethyl ether (-24 °C). 

Compare the normal boiling point of ethanol (78.2°C) with a molar mass of 46.07 g-moP to that of pentane (36.0°C) with a molar mass of 72.14 g-moP. ... 

The enthalpy of vaporization of ethanol is43.5 kJ mol (see Table 6.2). We will assume that the enthalpy of vaporization is approximately the same at ambient conditions as it would be at the boiling point of ethanol. 

Neither the handkerchief nor the banknote have suffered any damage, because only the alcohol burns. The flame has the characteristic yellow color of sodium. The boiling point of ethanol is 78 C, while its flash point is 12 °C. 

Comparing Ethylene glycol is a molecule with the formula C2H4(OH)2. Each molecule has two O—H bonds. Ethanol, C2H5OH, has one O—H bond. How would you expect the boiling points of ethanol and ethylene glycol to compare ... 

Convert (a) 327.5°C (the melting point of lead) to degrees Fahrenheit (b) 172.9°F (the boiling point of ethanol) to degrees Celsius and (c) 77 K, the boiling point of liquid nitrogen, to degrees Celsius. 

Suppose that a new temperature scale has been devised on which the melting point of ethanol ( - 117.3°C) and the boiling point of ethanol (78.3°C) are taken as 0°S... 

The normal boiling point of ethanol, C2H5OH, is 78.3°C, and its molar heat of vaporization is 39.3 kj/mol (Appendix E). What would be the vapor pressure, in torr, of ethanol at 50.0°C ... 

Check Round off to check the math. The change is in the right direction higher P should occur at higher 7. As we discuss next, a substance has a vapor pressure of 760 torr at its normal boiling point. Checking the CRC Handbook of Chemistry and Physics shows that the boiling point of ethanol is 78.5°C, very close to our answer. 

The boiling point of ethanol (C2H5OH) changes from 78.5°C to 85.2 C when an amount of naphthalene (CioHs) is added to 1.00 kg of ethanol. How much naphthalene, in grams, is required to cause this change Refer to Table 14.5 for needed data. 

Using the vapor-pressure curves in Figure 11.25, (a) estimate the boiling point of ethanol at an external pressure of 200 torn (b) estimate the external pressure at which ethanol will boil at 60 °C (c) estimate the boiling point of diethyl ether at 400 torn (d) estimate the external pressure at which diethyl ether will boil at 40 "C. 

The vapour wiU be at about 78 °C, the boiling point of ethanol. Thus, the distillate (the liquid collected in the receiving vessel) will be mainly ethanol. Liquid remaining in the flask is mainly water. 

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