315
Moisture 1.001
Volatile matter 35.484
Fixed carbon 50.172
Ash 12.028
-------
100.000
What is there about this requiring explanation?
4. Calculate the percentage of carbonic acid in a mineral from the
following data:--
Weight of apparatus and acids 87.0888 grams
" " " plus mineral 88.8858 "
" " " after loss of carbonic acid 88.1000 "
5. A sample of pig iron contains 1.43 per cent. of "combined" and 2.02
per cent. of "free" carbon. Taking 2 grams of it for each determination,
what weight of CO_{2} will be got on burning the residue from solution
in ammonium cupric chloride, and what from the residue after solution in
hydrochloric acid?
BORON AND BORATES.
Boron occurs in nature as boric acid or sassoline (H_{3}BO_{3}); borax
or tincal (Na_{2}B_{4}O_{7}.10H_{2}O); ulexite or boronatrocalcite
(2CaB_{4}O_{7}.Na_{2}B_{4}O_{7}); borocalcite (CaB_{4}O_{7}.4H_{2}O);
boracite, 2Mg_{3}B_{8}O_{15}.MgCl_{2}, and some other minerals. Boric
acid is also a constituent of certain silicates, such as tourmaline,
axinite, and datholite.
The natural borates are used in the preparation of borax, which is
largely employed as a preservative agent, for fluxing, and for other
purposes.
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