Properties of Aqueous Mixtures and Solutions. 1 59 



Percentage of 



Specific heat 



Specific heat 





alcohol, by weight. 



found. 



calculated. 





5 



101*502 







IO 



103-576 



96-043 



+ 7*533 



20 



1 04" 3 62 



92086 



12*276 



30 



I02'602 



88*129 



14-473 



40 



96-805 



84-172 



12*633 



45 



94-192 



82*193 



11999 



5° 



90-633 



80*215 



10*418 



60 



84-332 



76*258 



8*074 



70 



78-445 



72*301 



6*144 



80 



71*690 



68*344 



3 "346 



90 



65*764 



64-387 



1*377 



100 



60*430 





1 



Section 2. Heat produced by the mixing of Alcohol and Water. 



This was estimated as follows : — The liquid which formed the 

 smallest portion of the mixture was sealed up in a thin glass bulb ; 

 this was then introduced into the calorimeter, the glass bulb was 

 broken, the mixture formed, and the rise in the temperature of the 

 calorimeter observed. 



The units of heat evolved in the formation of 5 grms. of each 

 mixture were thus calculated, and found to be — 



10 per cent. 



spirit . 



.. 26-6850 



50 per cent. 



spirit . . 



. 35-5850 



20 „ 



jj 



. . . 43-9545 



60 



a • • 



. 27-2620 



30 



j> 



. . 47-9800 



70 „ 



a 



. 18-8200 



40 



>> 



. . 44-8630 



80 



>y ' * 



. 12-4775 



45 



a 



.. 38-8095 



90 



>> 



. 7*7025 



Section 3. Boiling-points. 

 A small flask was taken ; into this 100 cub. centims. of the mixture 

 was introduced, and the mouth of the flask closed by a doubly perfo- 

 rated cork. Into one of these perforations a thermometer was intro- 

 duced, into the other a bent tube, dipping beneath the surface of the 

 liquid in the flask, and connected at its other extremity with a Liebig 

 condenser. This tube had a lateral opening (inside the flask) just 

 beneath the cork ; by means of this the vapour escaped to the con- 

 denser, and trickled back into the flask after being condensed. Thus 



Percentage of 



Boiling-point 



Boiling-point 



Difference. 



alcohol, by weight. 



observed. 



calculated *. 







99'4 







10 



90*98 



97-25 



— 6*27 



20 



86*50 



95-10 



-8*6o 



30 



84*01 



92-95 



-8*94 



40 



82*52 



90*90 



-8*38 



45 



81-99 



89*72 



-7'73 



5° 



8i-33 



88-6o 



-7*27 



60 



8o*47 



86*50 



— 6*03 



70 



79-61 



84-35 



-474 



80 



78*84 



82*20 



-3-36 



90 



78-01 



80-05 



— 2*04 



100 



77-89 







* Calculated on the assumption that the alcohol and water in a mixture have 

 an influence on the boiling-point of the mixture proportional to their respective 

 weights. 



