Litre atmosphere

A convenient unit for gaseous expansion is obtained by measuring p in standard atmospheres and v in litres the work done by expansion through a volume of 1 litre under a constant pressure of one atmosphere is called a litre-atmosphere (1. atm,). Its value in ergs or other units may be calculated as follows ... 

Liquids, miscible, 382 partially miscible, 406 immiscible, 409 Litre-atmosphere, 48 Luther s rule, 480... 

Mass of ampoule, g Ditto, with liquid being tested, g Mass of liquid being tested, g Volume of displaced air, litre Atmospheric pressure, mmHg Temperature, °C... 

Using the ordinary units, the right-hand side of this equation would be expressed in litre-atmospheres, and the left in calories. 

If we wish to express the osmotic pressure in atmospheres, we must take 22=0-082 litre-atmospheres. dx... 

In order to obtain the pressure in atmospheres, it is necessary to multiply the heat of evaporation, which is usually expressed in calories, by the caloric equivalent of the litre atmosphere, viz. 24-1 (see p. 99). 

Here v is the volume of the solution which contains 1 mol. of solute and c is the number of mols. in unit volume (1 litre) of the solution. When R is expressed in litre-atmospheres (72 = 0-082), the equation gives the osmotic pressure tt in atmospheres. 

It is often necessary to calculate the work done in the expansion of a gas. The unit of work used here is the litre-atmosphere, i.e. the work done when the volume of a gas is increased by 1 litre at a constant pressure of 1 atmosphere. By p. 99, we have... 

Problem 7. Calculate the value of R in litre-atmosphere, if the osmotic pressure of a solution containing 45 g of sucrose dissolved per litre of solution at 2°C is 3.0 atmospheres. 

Method 1. Equip a 1 litre three-necked flask (or bolt-head flask) with a separatory funnel, a mechanical stirrer (Fig. II, 7, 10), a thermometer (with bulb within 2 cm. of the bottom) and an exit tube leading to a gas absorption device (Fig. II, 8, 1, c). Place 700 g. (400 ml.) of chloro-sulphonic acid in the flask and add slowly, with stirring, 156 g. (176 ml.) of pure benzene (1) maintain the temperature between 20° and 25° by immersing the flask in cold water, if necessary. After the addition is complete (about 2 5 hours), stir the mixture for 1 hour, and then pour it on to 1500 g. of crushed ice. Add 200 ml. of carbon tetrachloride, stir, and separate the oil as soon as possible (otherwise appreciable hydrolysis occurs) extract the aqueous layer with 100 ml. of carbon tetrachloride. Wash the combined extracts with dilute sodium carbonate solution, distil off most of the solvent under atmospheric pressure (2), and distil the residue under reduced pressure. Collect the benzenesulphonyl chloride at 118-120°/15 mm. it solidifies to a colourless sohd, m.p. 13-14°, when cooled in ice. The yield is 270 g. A small amount (10-20 g.) of diphen3 lsulphone, b.p. 225°/10 mm., m.p. 128°, remains in the flask. 

Place 35 ml. of a M solution of aluminium tsopropoxide or 7 g. of solid aluminium tsopropoxide, 450 ml. of dry isopropyl alcohol and 21 g. of purified benzaldehyde (Section IV,115) in a 1 litre round-bottomed flask. Fit a short reflux condenser (no water in the cooling jacket) or better a Hahn condenser (2) (containing a 1 cm. layer of ethyl alcohol in the iimer tube) to the flask and arrange for slow distillation from a water bath at the rate of 3-6 drops per minute. Continue the heating until a negative test for acetone is obtained after 5 minutes of total reflux (6-9 hours) if the volume of the mixture falls below 200 ml. during the reduction, add more isopropyl alcohol. Remove the reflux or Hahn condenser and distil off (Fig. II, 13, 3) most of the isopropyl alcohol under atmospheric pressure from a suitable oil bath. Hydrolyse the... 

Ethyl phenylethylmalonate. In a dry 500 ml. round-bottomed flask, fitted with a reflux condenser and guard tube, prepare a solution of sodium ethoxide from 7 0 g. of clean sodium and 150 ml. of super dry ethyl alcohol in the usual manner add 1 5 ml. of pure ethyl acetate (dried over anhydrous calcium sulphate) to the solution at 60° and maintain this temperature for 30 minutes. Meanwhile equip a 1 litre threenecked flask with a dropping funnel, a mercury-sealed mechanical stirrer and a double surface reflux condenser the apparatus must be perfectly dry and guard tubes should be inserted in the funnel and condenser respectively. Place a mixture of 74 g. of ethyl phenylmalonate and 60 g. of ethyl iodide in the flask. Heat the apparatus in a bath at 80° and add the sodium ethoxide solution, with stirring, at such a rate that a drop of the reaction mixture when mixed with a drop of phenolphthalein indieator is never more than faintly pink. The addition occupies 2-2 -5 hoius continue the stirring for a fiuther 1 hour at 80°. Allow the flask to cool, equip it for distillation under reduced pressure (water pump) and distil off the alcohol. Add 100 ml. of water to the residue in the flask and extract the ester with three 100 ml. portions of benzene. Dry the combined extracts with anhydrous magnesium sulphate, distil off the benzene at atmospheric pressure and the residue under diminished pressure. C ollect the ethyl phenylethylmalonate at 159-160°/8 mm. The yield is 72 g. 

Figure 1 The solubility of the prineipal atmospherie gases in seawater, as a funetion of temperature. Units are millilitres of gas eontained in a litre of seawater of salinity 35 psu, assuming an overlying atmosphere purely of eaeh gas. Note that salinity is defined in terms of a eonduetivity ratio of seawater to a standard KCl solution and so is dimensionless. The term praetieal salinity unit , or psu, is often used to define salinity values, however. It is numerieally praetieally identieal to the old style unit of parts per thousand by weight...

Evaporation of liquid to form vapour is accompanied by a considerable increase in volume. For example, at atmospheric pressure one volume of water will generate 1600 volumes of steam. Similarly 4.54 litres of gasoline will yield 0.93 m of neat vapour on complete vaporization. The reverse process, condensation, is accompanied by a considerable - and often rapid - decrease in volume. As a result ... 

As a compound water is remarkable. It is the only inorganic liquid to occur naturally on earth, and it is the only substance found in nature in all three physical states, solid, liquid and vapour (Franks, 1983). It is the most readily available solvent and plays a vital role in the continuation of life on earth. Water circulates continuously in the enviromnent by evaporation from the hydrosphere and subsequent precipitation from the atmosphere. This overall process is known as the hydrologic cycle. Reports estimate that the atmosphere contains about 6 x 10 litres of water, and this is cycled some 37 times a year to give an annual total precipitation of 224 X 10 litres (Franks, 1983 Nicholson, 1985). 

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