Which reaction is exothermic? ch4 + 2o2 mc016-1.jpg co2 + 2h2o + 891 kj nh4no3 + h2o + 25 kj mc016-2.jpg nh4+(aq) + no3-(aq) 2h2o + 286 kj mc016-3.jpg 2h2 + o2 n2 + o2 + 181 kj mc016-4.jpg 2no

It is simple. to determine if a reaction is exothermic, the heat of the reaction (kilojoules- kJ) are on the right side of the reaction. If heat is on the left, it's endothermic. 

so, the first choice is exothermic. 

Option (a) is the correct answer.

Explanation:

Exothermic reactions are the reactions in which heat is released. Whereas when there is absorption of heat then the reaction is known as endothermic reaction.

Thus, out of the given chemical equations, the equation [tex]CH_{4} + 2O_{2} \rightarrow CO_{2} + 2H_{2}O + 891 KJ shows that energy has been released. Therefore, this reaction equation is exothermic.

The correct answer for the question that is being presented above is this one: "a. condensation, dialysis. " The set of techniques that can be used for separating mixtures is that condensation, dialysis. Condensation refers to the change of water from its gaseous form (water vapor) into liquid water. On the other hand, dialysis is a process for removing waste and excess water from the blood.