It happened, indeed, that a certain sailor obtained in exchange for a shoelace tips as much worth of gold as would equal three g
olden coins; and likewise other things for articles of very little value, especially for new silver coins, and for some gold coins, to obtain which they gave whatever the seller desired, as for instance an ounce and a half and two ounces of gold, or thirty and forty pounds of cotton, with which they were already acquainted. They also traded cotton and gold for pieces of bows, bottles, jugs and jars, like persons without reason, which I forbade because it was very wrong; and I gave to them many beautiful and pleasing things that I had brought with me, no value being taken in exchange… Sourcing: Is this source a reliable source for researching the interactions between Christopher Columbus and Indigenous Peoples? Why or why not???
As chamas do oxiacetileno são usadas para soldas, atingindo temperaturas próximas a 2000oC. Estas temperaturas são devidas à combustão do acetileno com o oxigênio: (dados: C=12/H=1/O=16)
1 C2H2(g) + 5/2 O2(g) → 2 CO2(g) + 1 H2O(g)
Segundo a reação, indique a massa de CO2 produzida com 9g H2O
