Classify each of the following as exothermic or endothermic:
a. CH₄(g) + 2O₂(g) $\xrightarrow{∆}$ CO₂(g) + 2H₂O(g) + 802kJ

Question

Classify each of the following as exothermic or endothermic:

a. CH₄(g) + 2O₂(g) $\xrightarrow{∆}$ CO₂(g) + 2H₂O(g) + 802kJ

Accepted Answer

Welcome back, everyone. We need to consider the reaction between ethane C two H six gas, oxygen gas, which forms carbon dioxide and vapor water as products. We're also told we have a third product being 1561 kilojoules of heat. And we need to determine whether the reaction is either endothermic or exothermic. So note that we have the figure plus 1561 kilojoules recognize that because this is written on the product side, this is expressed as heat that is released from our reaction. So because we have the release of thermal energy from our system being our reaction to the surroundings, we will therefore recall our understanding of an exothermic reaction which is described as a reaction which has bond formation which are formed in our products. We would have the release of heat, which therefore corresponds to a loss of energy and this energy is given off to our surroundings. So we have an increase in energy of our surroundings. This will thus correspond to an entropy change which is negative. And recall that entropy change describes the heat exchange in our reaction. So the energy of our reactants will be greater than the energy of our products corresponding to this negative entropy change. So based off of the fact that we noted down that we have plus 1561 kilojoules as our product written in our equation, we have this amount of heat released. And therefore, our final answer is going to be that the reaction is going to be exothermic. Now, if we were to have an endothermic reaction, we would recall that the definition correlates to bond's breaking on a reactant side which will correlate to an absorption of heat. So our reactants will absorb energy, they require energy. We will have a gain in energy via that absorption of heat. And because energy must be gained, we will therefore have a decrease in the energy of our surroundings corresponding to a decrease in the temperature Of our surroundings. And recall that for an endothermic reaction, we have a positive entropy change. So the energy of our reactants are less than the energy of our products, our products have higher energy and an endothermic reaction. However, as we confirmed, because 1,561 kg of heat is released, we have an exothermic reaction and that is our final answer. I hope this made sense. And let us know if you have any questions.

Classify each of the following as exothermic or endothermic:
a. CH₄(g) + 2O₂(g) $\xrightarrow{∆}$ CO₂(g) + 2H₂O(g) + 802kJ

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Classify each of the following as exothermic or endothermic:
a. CH₄(g) + 2O₂(g) $\xrightarrow{∆}$ CO₂(g) + 2H₂O(g) + 802kJ