102 GENERAL SCIENCE 



M-quid is* Called the solvent and the solid the solute. Of 

 course the salt did not really disappear. Invisible 

 particles of it are held in the water, as is shown by the 

 fact that the water tastes salty. The salt water obtained 

 is called a solution. If the solid is some other color than 

 white, the water solution of it will be colored ; but the 

 solution will always be clear even if colored. An insoluble 

 substance like starch, powder, lime, or clay can be scat- 

 tered through the water by shaking, but the mixture 

 will be turbid. Such a mixture of a solid and a liquid 

 is called a suspension. If allowed to stand long enough, 

 the suspended material will settle to the bottom, leaving 

 the liquid clear. In the case of a solution, however, 

 there is no settling of the solute. 



If we continue to add salt to a definite volume of water, 

 there will come a time when the salt is no longer dissolved. 

 The solution is then said to be saturated, and if more 

 salt is added, it simply falls to the bottom. 100 grams 

 of water at C. will dissolve 35.5 grams of salt and no 

 more. If the water is heated, the amount of salt that 

 it will dissolve is increased slightly. In the case of some 

 solids, the effect of heating the water is more marked than 

 with salt. 



Tinctures are solutions in which alcohol is the solvent. 



Properties of Solutions. As we have stated before, 

 the taste and color of the solutes are imparted to the 

 solution. A small bit of potassium permanganate will 

 be sufficient to color a large quantity of water. As a 

 usual thing it will be found that as water dissolves 

 salts, the volume will increase, and it will be found that 

 the water has been otherwise changed. It boils at a 

 higher temperature than it did before, and freezes at a 

 lower temperature ; a saturated solution of common salt 



