SUBSTANCES AND PROPERTIES 7 



of 1 c.c., see Appendix I), the color and the solubility or non-solu- 

 bility in water. In the case of liquids, the temperature at which 

 the liquid boils under atmospheric pressure (the boiling-point), 

 the specific gravity, the mobility, the odor and the color (if any) 

 are never exactly the same for any two different liquids. We shall 

 learn more about these properties as occasions for using them 

 arise. 



Attributes and Conditions. It should be noted that 

 mass is not a specific property. Different specimens of a given 

 substance may have different masses, but they all have the same 

 specific properties. The mass of each, although fixed, is a quality 

 of that particular specimen only. So is it with the volume and 

 the dimensions of a specimen. These are attributes of a specimen. 



Again the temperature is not a specific property. There is no 

 particular temperature peculiar to quartz. Even the very same 

 specimen may be at different temperatures at different times. 

 Temperature and pressure are variable and are called conditions. 

 The temperature or the pressure of a specimen may be changed 

 at will. But the specific properties of a substance under any 

 given conditions cannot be changed, so long as we have to do 

 with the same substance. 



Law of Chemical Change. When the wool was boiled 

 with caustic soda solution, it was in some way acted upon by 

 the caustic soda. It became soluble, and disappeared into the 

 liquid. Wool will not dissolve in boiling water. But in the 

 former operation its material acquired at least one new property, 

 namely that of being soluble. Since we have defined a substance 

 as a species of matter, with a definite set of specific properties, 

 we are compelled to decide that when a piece of material changes 

 its properties, it has, in doing so, become a new substance. This 

 experiment, then, calls our attention to the second of the funda- 

 mental laws of chemistry, namely that material forming one or 



