204 



HEAT OF FORMATION OF THE NITRATES. 



]sr 2 + 5 4- BaO = Ba(N0 3 ) 2 liberates 4- 47'2. 

 From the dissolved base, the salt also being dissolved, 4- 28*2. 



7. It may be remarked that the heat of formation of the 

 alkaline and alkaline-earthy nitrates, by means of gaseous 

 nitrogen, gaseous oxygen, and the dissolved base, is* sensibly the 

 same for all. The same figure (4- 28 1) applies equally to 

 magnesium nitrate, as it is formed from solid magnesium 

 hydrate. 



8. The formation of the anhydrous nitrates from the 

 anhydrous base and anhydrous nitric acid, whether gaseous or 

 solid, is given in the tables on p. 126. Similarly, the forma- 

 tion of the solid nitrates, formed by solid hydrated nitric acid 

 and basic hydrates also solid, is given in the table on p. 127. 



9. We should further note that the metamorphosis of the 

 alkaline nitrites into nitrates M(N0 2 ) 2 dissolved 4- 2 = 

 M(N0 3 ) 2 dissolved, liberates a quantity of heat nearly equal 

 to 4- 21 f 7, and sensibly the same whatever be the base of the 

 salt (p. 178). 



10. The heat of formation of the anhydrous magnesium, iron, 

 cobalt, nickel, and manganese nitrates, cannot be calculated, 

 these salts being only known in the hydrated state. In the 

 dissolved state we have, from the metals and the metallic 

 oxides 



N 2 + 6 + Mg 

 N 2 + 6 + Mn 

 N 2 + 6 -f Fe 

 N 2 + 6 + Zn 

 N 2 + 6 + Co 

 N 2 + 6 + Ni 

 N 2 + 6 + Cd 

 N 2 + 6 + Cu 



11. The formation of lead nitrate from the elements 



N 3 4- 6 4- Pb = Pb(N0 3 ) 2 anhydrous liberates 4- 52'8. 



That of the dissolved salt 4- 48'7. 



The formation of the same salt from the anhydrous oxide, 

 N 2 4- 5 4- PbO = Pb(N0 3 ) 2 , liberates 4- 27'3. 



The dissolved salt 4- 23'2. 

 The formation of silver nitrate from the elements 



N 2 4- 6 4- Ag 2 = 2AgN0 3 anhydrous liberates 4- 28'7. 



That of the dissolved salt 4- 23'0. 

 The formation of the same salt from the oxide, 



N 2 4- 5 4- Ag 2 = 2AgN0 3 , 4- 25-2. 

 The dissolved salt 4- 19'5. 



12. We will add the following general remarks. Between 

 the formation of two salts obtained by the union of the 



