What is the difference between a temperature of 12f and a temperature of -5f?

The answer for #3 is c but i don't know why

Hydrogenation reactions, in which h2 and an "unsaturated" organic compound combine, are used in the food, fuel, and polymer industries. in the simplest case, ethene (c2h4) and h2 form ethane (c2h6). if 140 kj is given off per mole of c2h4 reacting, how much heat (in mj) is released when 12 kg of c2h6 forms?

Areader can tell that the meaning of “obnoxious” will include “having the quality of something” because of the .a) prefix b)pronunciation c)suffix d) word root