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Exothermic vs. Endothermic

Posted: Sun Jan 27, 2019 5:49 pm
Can someone please explain the difference between endothermic and exothermic?

Re: Exothermic vs. Endothermic

Posted: Sun Jan 27, 2019 5:57 pm
Exothermic reactions favor the formation of products and give off heat. Endothermic reactions favor the formation of reactants and require heat.

Re: Exothermic vs. Endothermic

Posted: Sun Jan 27, 2019 6:04 pm
An exothermic reaction has a negative delta H while an endothermic reaction has a positive delta H. Delta H=Change in enthalpy.

Re: Exothermic vs. Endothermic

Posted: Mon Jan 28, 2019 1:12 am
The two posts before are really standard definitions. In other words, you can simply regard the exothermic reaction as a "releasing heat" process. On the other hand, you can regard endothermic reaction as an "absorbing heat" process.

Re: Exothermic vs. Endothermic

Posted: Mon Jan 28, 2019 8:34 am
Exothermic is a reaction that releases heat. Its delta H is negative, < 0. Endothermic is a reaction that absorbs heat from its environment. Its delta H is positive, > 0.

Re: Exothermic vs. Endothermic

Posted: Mon Jan 28, 2019 9:55 am
Endothermic has a positive delta G and exothermic has a negative delta g. Endothermic requires heat and exothermic releases heat. Endothermic favors product formation and exothermic favors reactant formation.

Re: Exothermic vs. Endothermic

Posted: Mon Jan 28, 2019 3:27 pm
Endothermic: When energy is absorbed from its surroundings. delta H>0
Exothermic: When energy is released. delta H<0

Re: Exothermic vs. Endothermic

Posted: Mon Jan 28, 2019 4:08 pm
If the reaction gives a release of heat (-delta H), the reaction is exothermic. If the reaction requires heat (+delta H), the reaction is endothermic.

Re: Exothermic vs. Endothermic

Posted: Tue Jan 29, 2019 6:52 pm
Professor Lavelle gave example of a hot/cold pack during lecture one day, and I thought it was helpful.

Endothermic reactions require heat to obtain the products (delta H = positive) while exothermic reactions release heat during reactions (delta H = negative). Given that, with a hot pack, when you break the bag in inside, it becomes warm. That’s because the bag inside the hot pack undergoes an exothermic reaction, meaning it’s giving off heat which causes the bag to warm up. For the cold pack, upon breaking the bag inside the pack, an endothermic reaction takes place. The reaction absorbs heat from the surrounding and uses to form its products, which is why the pack turns cold.

Hope this helps!

Re: Exothermic vs. Endothermic

Posted: Wed Jan 30, 2019 12:11 am
Exothermic reactions release energy, delta H is negative, and heat is a product. Endothermic reactions absorb energy, delta H is positive, and heat is a reactant.

Re: Exothermic vs. Endothermic

Posted: Wed Jan 30, 2019 1:36 pm