56 CHEMISTRY AND HEAT 



COMMON NAMES OF CHEMICAL COMPOUNDS 



by weight, and the molecule contains 2 -f 16 = 18 parts. The 

 weight of the molecule of a substance is termed the molec 

 weight. 



HEAT 



TEMPERATURE 



Thermometric Scales. Three different scales are used 

 designating temperatures, namely, the Fahrenheit scale, the 

 centigrade scale, and the Reaumur scale. The last-named 

 is little used, however. Temperatures on these scales are 

 usually indicated by the abbreviations F. or Fahr., C. or Cent., 

 and R. or Reau., respectively. There are three standard points 

 on each scale, namely, the boiling point of water, at sea level, 

 the melting point of ice, and the absolute zero of temperature. 

 The last indicates the point of complete absence of heat. On 

 the Fahrenheit scale, the melting point of ice is marked 32 

 and the boiling point of water is marked 212, and the inter- 

 vening space is divided into 180 equal parts, called degrees. 







