What is the term used for reactions such as this where oxygen and organic compounds (methane) react to form water and carbon dioxide?

if you're asking what comes out, it's steam.

o conteúdo de calor de um sistema é igual à entalpia apenas para um sistema que é constante

weight of any object is given by

w = m*g

where m is mass of the object and g is the acceleration due to gravity.

for earth the value of g is 9.8 m/s^2 so

w=117.6 n m=12 g=?

117.6=12g => g=9.8 m/s^2

which is the force of gravity on earth.