Endothermic v. Exothermic

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Samantha Lee 1A
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Endothermic v. Exothermic

Postby Samantha Lee 1A » Wed Jan 20, 2021 11:28 am

In class today, we learned about endothermic reactions in depth (vaporization, fusion, sublimation) and that the have a positive delta H. Will they ALWAYS have a positive delta H? Does that mean that exothermic reactions will ALWAYS have a negative delta H?

Are there any exceptions to this rule?

Andrew Wang 1C
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Re: Endothermic v. Exothermic

Postby Andrew Wang 1C » Wed Jan 20, 2021 11:37 am

I assume that's the case, since the sign of delta H is kind of "built in" to the definitions of endothermic and exothermic. Negative delta H means heat is released, so it's exothermic, while positive means heat is absorbed which is endothermic.

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Re: Endothermic v. Exothermic

Postby Chem_Mod » Wed Jan 20, 2021 11:38 am

Yes, endothermic reactions will always have a positive delta H, and exothermic reactions will always have a negative delta H.

Frankie Mele 3J
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Re: Endothermic v. Exothermic

Postby Frankie Mele 3J » Wed Jan 20, 2021 11:39 am

I think that endothermic reactions will always have a positive change in enthalpy because in order for the reaction to be classified as endothermic in the first place, heat must be absorbed.

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Re: Endothermic v. Exothermic

Postby Rahul Sobti 1E » Wed Jan 20, 2021 11:43 am

Yes. Endothermic reactions will always have a positive Delta H as they are absorbing energy so the products will have more energy than the reactants. Same with exothermic reactions, Delta H will always be negative because the products will have less energy than the reactants.

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Re: Endothermic v. Exothermic

Postby JonathanSung_2G » Wed Jan 20, 2021 11:55 am

Whether heat is absorbed or released determines if the reaction is endothermic or exothermic. A reaction that absorbs heat will be endothermic with a positive delta H.

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Re: Endothermic v. Exothermic

Postby Libby Dillon - 1A » Wed Jan 20, 2021 11:57 am

Yes, I believe the value of delta H (positive or negative) is the determining factor of whether something is endothermic or exothermic. In an endothermic reaction, heat is required, so delta H will always be positive. In an exothermic reaction, heat is released, so delta H will always be negative.

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Re: Endothermic v. Exothermic

Postby Emmeline Phu 1G » Wed Jan 20, 2021 12:11 pm

Hi! Yes, endothermic reactions will always have a positive enthalpy indicating the absorption of heat whereas exothermic reactions will always have a negative enthalpy indicating the release of heat. Hope this helps! :)

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Re: Endothermic v. Exothermic

Postby KhanTran3K » Wed Jan 20, 2021 12:14 pm

I do not believe that there are any exceptions to the rule, and you are correct. This is due to the nature of "delta H" itself. Delta H is the change in enthalpy. So, when you have a positive value, it tells us that the enthalpy in the products is higher than the reactants, which mean it requires energy or heat to get it to change. With this, the opposite is true for exothermic reactions, or negative delta H values.

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Re: Endothermic v. Exothermic

Postby My-Lan Le 1L » Wed Jan 20, 2021 12:21 pm

Yes, I think those statements should always be true. You can tell if a reaction is exothermic or endothermic by calculating its delta H. If it is positive, the reaction is endothermic, and if it is negative, the reaction is exothermic. This statement would make sense because H is enthalpy which is the amount of heat released or absorbed, which is basically also showing whether the reaction is exothermic or endothermic in the process.

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Re: Endothermic v. Exothermic

Postby Ria Nawathe 1C » Wed Jan 20, 2021 12:28 pm

Just a side note: fusion, vaporization, and sublimation aren't really reactions because there aren't any chemical bonds being broken, they're considered phase changes and are physical changes because it's just the intermolecular attractions that are being overcome.

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Re: Endothermic v. Exothermic

Postby DMaya_2G » Wed Jan 20, 2021 12:50 pm

Endothermic reactions will have a positive delta H because the reaction requires heat. In contrast, exothermic reactions will have a negative delta H because the reaction gives a net release of heat.

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Re: Endothermic v. Exothermic

Postby Inderpal Singh 2L » Wed Jan 20, 2021 1:18 pm

I do not believe there are any exceptions to this rule. Exothermic means releasing heat, so a positive delta H would not be possible. The vice versa applies to endothermic, which takes in heat, so a negative delta H would not be possible.

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Re: Endothermic v. Exothermic

Postby Joseph_Armani_3K » Wed Jan 20, 2021 3:42 pm

I believe so; endothermic reactions will always have a positive enthalpy and exothermic reactions will always have a negative enthalpy.

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Re: Endothermic v. Exothermic

Postby Karl Yost 1L » Wed Jan 20, 2021 3:44 pm

Endothermic reactions always have a +ve delta H, while exothermic reactions always have a -ve delta H.

I don't believe that there are any exceptions to this rule.

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Re: Endothermic v. Exothermic

Postby BoparaiAdeshsurjit2F » Wed Jan 20, 2021 6:27 pm

Yes if you are losing heat from the system,endothermic, the delta h will be negative

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Re: Endothermic v. Exothermic

Postby Vanshika Bhushan 1A » Wed Jan 20, 2021 7:47 pm

An endothermic process has a positive delta H because the system is gaining heat. An exothermic process has a negative delta H because the system is losing heat.

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Re: Endothermic v. Exothermic

Postby Moura Girgis 1F » Wed Jan 20, 2021 9:01 pm

That's right, since exothermic reactions will be losing heat, that means that the delta h must be negative.

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Re: Endothermic v. Exothermic

Postby Ariel Guan 1H » Thu Jan 21, 2021 12:12 am

yea, endothermic rxns will always have a positive delta H, and exothermic rxns will always have a negative delta H

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Re: Endothermic v. Exothermic

Postby Lorraine Jiang 2C » Thu Jan 21, 2021 12:54 am

Yes, that is correct! Exothermic reactions always have a negative delta H, and an endothermic reaction will always have a positive delta H.

Hope it helps!

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Re: Endothermic v. Exothermic

Postby Olivia Smith 2E » Thu Jan 21, 2021 8:54 am

Yes exothermic will always have a delta - H and endothermic will always have a positive delta H as that is the definition. negative delta H means that the system is releasing energy and positive delta H means

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Re: Endothermic v. Exothermic

Postby Pierce Newman 1A » Thu Jan 21, 2021 11:19 am

Endothermic reactions always have net positive delta H and exothermic reations always have net negative delta H, but for differing reactions you could have different "paths". For example if you burn glucose in the lab there is one exothermic step, but in the body there are many, with some exothermic and some endothermic(energy investment) steps. But enthalpy is a state property, meaning both reactions have overall net negative delta H and they are both considered to be favorable or exothermic.

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Re: Endothermic v. Exothermic

Postby Samudrala_Vaishnavi 3A » Fri Jan 22, 2021 7:48 am

Yes, I would say so in my opinion but I don't know if there any exceptions out there. To be clear, sublimation, vaporization, and fusion all are endothermic to begin with and you have to add heat to the system for there to be a phase change from ice to steam, that is why they all have positive delta H values. Since the change in enthalpy basically corresponds to the absorption of heat by a system, and exothermic reactions release heat, there has to be a negative delta H value.

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Re: Endothermic v. Exothermic

Postby Claudia_Danysh_2B » Fri Jan 22, 2021 10:49 am

Yes, a negative delta H is always going to be exothermic because it released heat in the process, making enthalpy a negative value. Additionally, a positive delta H value will always be endothermic because it required heat in the process!

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Re: Endothermic v. Exothermic

Postby aashmi_agrawal_3d » Fri Jan 22, 2021 3:42 pm

Yes, because a positive delta H is absorbing heat and a negative delta H is releasing heat.

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Re: Endothermic v. Exothermic

Postby Yeonjoo Kim 2B » Fri Jan 22, 2021 4:06 pm

Exothermic reactions will always be negative because the total energy of the products is less than that of the reactants which is why energy gets released.

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Re: Endothermic v. Exothermic

Postby Joshua Swift » Fri Jan 22, 2021 4:18 pm

Endothermic reactions will always have a +H and exothermic reactions will have a -H. if heat is showed in the reaction on the reactants side it is endothermic and if it is present on the products side it is an exothermic reaction.

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Re: Endothermic v. Exothermic

Postby Jonathan Malau 1F » Fri Jan 22, 2021 5:37 pm

Yes, endothermic reactions will always have a positive delta H (meaning that it absorbs energy), and exothermic reactions will always have a negative delta H (as it releases energy).

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Re: Endothermic v. Exothermic

Postby Alen Huang 2G » Fri Jan 22, 2021 6:35 pm

Yes! Endothermic reactions will always have a positive enthalpy change and exothermic reactions will always have a negative enthalpy change.

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Re: Endothermic v. Exothermic

Postby Aayushi Jani 3A » Fri Jan 22, 2021 6:49 pm

Yes, endothermic reactions have a positive delta H since they require energy while exothermic reactions have a negative delta H since they release energy.

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Re: Endothermic v. Exothermic

Postby Jiapeng Han 1C » Fri Jan 22, 2021 8:21 pm

I think at least according to the definition, endothermic reaction has positive H while exothermic reaction has negative H.

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Re: Endothermic v. Exothermic

Postby Jiayi Wu 3J » Fri Jan 22, 2021 9:00 pm

I think so, if the sign changes, their property would change too, so endothermic reaction would be exothermic

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Re: Endothermic v. Exothermic

Postby Margaret Xu 3C » Fri Jan 22, 2021 9:40 pm

I believe you're right! When the enthalpy is positive, we can think of the endothermic reaction as heat going into the system, so the increase in heat is represented with +. When the enthalpy is negative, the endothermic reaction releases--or loses-- heat, so the decrease in heat in the overall system is -.

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Re: Endothermic v. Exothermic

Postby Devin Patel 2D » Fri Jan 22, 2021 10:01 pm

An endothermic reaction will always have a positive delta H because, for a reaction to endothermic, it absorbs heat. An exothermic reaction will always be a negative delta H because, for a reaction to be exothermic, it gives off heat.

Brian Nguyen 2I
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Re: Endothermic v. Exothermic

Postby Brian Nguyen 2I » Sun Jan 24, 2021 7:34 am

Yes, this is definitely true. Exothermic reactions are always labeled by a negative delta H, whereas endothermic reactions are always labeled by a positive delta H. This is due to how exothermic reactions release heat, whereas endothermic reactions absorb heat.

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Re: Endothermic v. Exothermic

Postby Alisa Nagashima 1B » Sun Jan 24, 2021 9:14 am

Yes, endothermic reactions absorb heat hence the negative delta H. Exothermic reactions release heat hence the positive delta H.

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Re: Endothermic v. Exothermic

Postby Javier Perez M 1H » Sun Jan 24, 2021 9:47 am

Definitely, use the delta H to determine whether is endothermic or exothermic.

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Re: Endothermic v. Exothermic

Postby Akemi Karamitsos 1E » Sun Jan 24, 2021 10:14 am

Delta H represents the change in enthalpy, which is the total heat content of a system. So yes, the positive or negative sign of delta H should be used to determine whether a reaction is endothermic or exothermic. When it is less than zero, this means that heat has been released from the system, indicating an exothermic reaction. Similarly, when it is greater than zero, heat has been absorbed, indicating an endothermic reaction.

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Re: Endothermic v. Exothermic

Postby Ziyan Peng 3A » Sun Jan 24, 2021 12:30 pm

Yes. You can also make sense of this by thinking about enthalpy being a state property. As long as the amount of heat is greater than the system began with, it is definitely endothermic, and vice versa for exothermic reactions.

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Re: Endothermic v. Exothermic

Postby Kat Stahl 2K » Sun Jan 24, 2021 12:44 pm

I don't think there are any exceptions to this rule! Exothermic reactions will have a negative delta H and endothermic reactions will have a positive delta H.

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Re: Endothermic v. Exothermic

Postby sophia kosturos 2B » Sun Jan 24, 2021 3:53 pm

that is correct, endothermic reactions will always have positive delta H values because they absorb heat and exothermic reactions will always have negative delta H values because they release heat.

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Re: Endothermic v. Exothermic

Postby Sai Ramadas 1J » Sun Jan 24, 2021 4:02 pm

I do think that these are always true because the definition of endothermic is that it requires heat (and exothermic releases heat). This probably means that endothermic reactions will always have a positive delta H and exothermic reactions will always have a negative delta H. I'm not sure if there are any exceptions, but I don't think we will need to know that for this class.

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Re: Endothermic v. Exothermic

Postby Shreyank Kadadi 3K » Sun Jan 24, 2021 4:40 pm

Yes, by definition an endothermic reaction requires heat (positive H) whereas an exothermic reaction expels heat (negative H

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Re: Endothermic v. Exothermic

Postby Hana Sigsbee 3B » Sun Jan 24, 2021 4:51 pm

Yes, endothermic reactions will always have a positive delta H because the change is positive and exothermic reactions will always have a negative delta H because the change is negative.

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Re: Endothermic v. Exothermic

Postby Luveia Pangilinan 1A » Sun Jan 24, 2021 4:52 pm

Yes that is right. I don't think there are any exceptions that can bend the rule for it but I'm pretty positive that's the case

David Y
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Re: Endothermic v. Exothermic

Postby David Y » Sun Jan 24, 2021 5:39 pm

Endothermic always has a positive delta (change in) H

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Re: Endothermic v. Exothermic

Postby Mingzi Yang 1E » Sun Jan 24, 2021 5:52 pm

Endothermic reactions have a positive delta H and exothermic reactions have a negative delta H.

Chance Herbert 3A
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Re: Endothermic v. Exothermic

Postby Chance Herbert 3A » Sun Jan 24, 2021 5:58 pm

Yes! Endothermic reactions will always have a positive delta H as the system absorbs energy while exothermic reactions release energy from the system, resulting in a negative delta H

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Re: Endothermic v. Exothermic

Postby Isabella Cortes 2H » Sun Jan 24, 2021 6:01 pm

yes!! endothermic reactions will always have a positive delta H and exothermic reactions will always have a negative delta H

Abhinav Behl 3G
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Re: Endothermic v. Exothermic

Postby Abhinav Behl 3G » Sun Jan 24, 2021 7:44 pm

Yep, endothermic reactions will always have a positive delta H, because this type of reaction takes in heat, thus it would have a positive change in enthalpy. On the other hand, exothermic reactions will have a negative delta H because you lose heat while the reaction is taking place, thus resulting in a negative change in enthalpy.

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Re: Endothermic v. Exothermic

Postby Edison Tham 3D » Sun Jan 24, 2021 7:46 pm

Yes! Any endothermic reaction would have a positive ∆H value and any exothermic reaction would have a negative ∆H value.

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Re: Endothermic v. Exothermic

Postby Ximeng Guo 2K » Sun Jan 24, 2021 8:25 pm

Exothermic reactions have a negative delta H and endothermic reactions have a positive delta H.

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Re: Endothermic v. Exothermic

Postby Hannah Lechtzin 1K » Sun Jan 24, 2021 8:30 pm

Yes, endothermic reactions will always have a positive delta H because it indicates that the reaction is taking in heat, while exothermic reactions will always have a negative delta H because that indicates that the reaction is giving off heat.

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Re: Endothermic v. Exothermic

Postby AJForte-2C » Sun Jan 24, 2021 8:59 pm

you can think of an endothermic reaction as the system you're viewing "gaining" enthalpy or heat. This would mean that your △H is positive.

Diana Aguilar 3H
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Re: Endothermic v. Exothermic

Postby Diana Aguilar 3H » Sun Jan 24, 2021 10:24 pm

Yes, like others have said, endothermic reactions will always have a positive delta H and exothermic reactions will always have a negative delta H

Abraham De Luna
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Re: Endothermic v. Exothermic

Postby Abraham De Luna » Sun Jan 24, 2021 10:51 pm

Endothermic reactions will always have a positive delta H whereas an exothermic reaction will always have a negative delta H.

Jaden Kwon 3C
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Re: Endothermic v. Exothermic

Postby Jaden Kwon 3C » Mon Jan 25, 2021 1:56 am

Yeah exothermic reactions also have a negative delta H and endothermic reactions always have a positive delta H because of the way exothermic reactions are defined as releasing energy while endothermic reactions are defined as absorbing energy.

Constance Newell
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Re: Endothermic v. Exothermic

Postby Constance Newell » Mon Jan 25, 2021 4:52 am

Exothermic reactions have a negative delta H and endothermic reactions have a positive delta H

Laura 3l
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Re: Endothermic v. Exothermic

Postby Laura 3l » Mon Jan 25, 2021 5:56 am

Endothermic will always be a positive enthalpy value and exothermic will always be a negative enthalpy value.

Nicoli Peiris 1B
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Re: Endothermic v. Exothermic

Postby Nicoli Peiris 1B » Mon Jan 25, 2021 12:18 pm

Yes endothermic reactions are always positive and exothermic reactions are always negative.

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Re: Endothermic v. Exothermic

Postby Katie Le 3K » Mon Jan 25, 2021 2:26 pm

There are no exceptions to this rule

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Re: Endothermic v. Exothermic

Postby Cora Chun 2D » Mon Jan 25, 2021 2:41 pm

Yes, I believe this is always the case. Endothermic reactions have a positive delta H, and exothermic reactions have a negative delta H. Vaporization and fusion are always endothermic (because you need to put in heat to get liquids to their gas state and solids to their liquid state), and condensation of gas into liquid and liquid to solid is exothermic.

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Re: Endothermic v. Exothermic

Postby jessicasilverstein1F » Thu Jan 28, 2021 11:19 am

Yes, this is true. Endothermic reactions will always have a + delta H, and exothermic reactions will always have a - delta H, this is the case for all

reyvalui_3g
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Re: Endothermic v. Exothermic

Postby reyvalui_3g » Fri Jan 29, 2021 11:13 pm

I do not believe that there are any exceptions to this rule.

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Re: Endothermic v. Exothermic

Postby Lorena_Morales_1K » Sat Jan 30, 2021 2:56 pm

Why is bond formation exothermic again?

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Re: Endothermic v. Exothermic

Postby Kayko Lee 1C » Sat Jan 30, 2021 3:39 pm

Lorena_Morales_1K wrote:Why is bond formation exothermic again?

I believe it's exothermic because the system loses energy to form the bonds and since there's a decrease in energy, the energy is lost as heat and makes the process exothermic

Taylor Newville 1C
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Re: Endothermic v. Exothermic

Postby Taylor Newville 1C » Sat Jan 30, 2021 5:01 pm

The definition of delta H is the change in enthalpy of a system. The definition of exothermic is that heat is released during a reaction and the enthalpy of the system decreases (which can only ever be represented by a negative delta H). The opposite is true of endothermic. So, you are right and there are no exceptions.

Taylor Newville 1C
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Re: Endothermic v. Exothermic

Postby Taylor Newville 1C » Sat Jan 30, 2021 5:10 pm

Lorena_Morales_1K wrote:Why is bond formation exothermic again?

Bonded atoms/molecules are more stable. Unbound atoms require energy to keep them apart which is released when they form a bond, making bond formation exothermic.

Chinmayi Mutyala 3H
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Re: Endothermic v. Exothermic

Postby Chinmayi Mutyala 3H » Sat Jan 30, 2021 5:18 pm

Yes, endothermic will be positive since it is absorbing heat and exothermic will be negative since it is releasing heat.

Alex Benson
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Re: Endothermic v. Exothermic

Postby Alex Benson » Sun Jan 31, 2021 10:52 am

Yes that will always be the case! I have not heard Lavelle or anybody else speak to any exceptions to the rule!

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Re: Endothermic v. Exothermic

Postby Morgan Gee 3B » Sun Jan 31, 2021 11:45 am

Endothermic reactions will always have a positive deltaH because they require energy. On the other hand, exothermic reactions will always have a negative deltaH because they release energy.

Shana Patel 1C
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Re: Endothermic v. Exothermic

Postby Shana Patel 1C » Sun Jan 31, 2021 11:59 am

Exothermic reactions will always be negative because the total energy of the products is less than that of the reactants which is why energy gets released.

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Re: Endothermic v. Exothermic

Postby Julianna_flores3E » Sun Jan 31, 2021 12:11 pm

Endothermic reactions will always be positive and exothermic reactions will always be negative.

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Re: Endothermic v. Exothermic

Postby Emma Strassner 1J » Sun Jan 31, 2021 2:13 pm

Endothermic reactions will always be positive because they require heat to occur, and exothermic reactions will always be negative because they release heat and therefore lose energy.

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Re: Endothermic v. Exothermic

Postby Rose_Malki_3G » Sun Jan 31, 2021 2:55 pm

Yes endothermic reactions will always have a positive enthalpy and exothermic reactions will always have a negative enthalpy/delta H

Charmaine Ng 2D
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Re: Endothermic v. Exothermic

Postby Charmaine Ng 2D » Sun Jan 31, 2021 3:00 pm

Yep, endothermic will always be positive, since an endothermic reaction always takes in energy, while exothermic will always be releasing, and therefore always negative :))

Aliya Roserie 3I
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Re: Endothermic v. Exothermic

Postby Aliya Roserie 3I » Sun Jan 31, 2021 3:24 pm

Yes! You are correct. I haven't heard of any exceptions to this rule.

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Re: Endothermic v. Exothermic

Postby apurva-3E » Sun Jan 31, 2021 3:30 pm

Yes, endothermic reactions will always have a positive deltaH values.

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Re: Endothermic v. Exothermic

Postby Muskaan Abdul-Sattar » Sun Jan 31, 2021 5:00 pm

Yes, you'll find that exothermic reactions will always have a negative delta H while endothermic reactions will always have a positive delta H. This is due to the fact that heat is either being released or absorbed.

rhettfarmer-3H
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Re: Endothermic v. Exothermic

Postby rhettfarmer-3H » Sun Jan 31, 2021 5:04 pm

yes, I think it is common that positive H is always endothermic and exothermic is always negative. There is no real expectation of these rules because H will always change based on the environment and changes.

Karina Grover 1A
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Re: Endothermic v. Exothermic

Postby Karina Grover 1A » Sun Jan 31, 2021 5:42 pm

Endothermic reactions are characterized by their positive "delta H" values. In endothermic reactions, temperature/heat can be treated as a "reactant." Thus, when temperature is increased, the reaction will shift to the right, and when temperature is decreased, the reaction will shift to the left.

Exothermic reactions are characterized by their negative "delta H" values. In exothermic reactions, temperature/heat can be treated as a "product." Thus, when temperature is increased, the reaction will shift to the left, and when temperature is decreased, the reaction will shift to the right.

MCalcagnie_ 1D
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Re: Endothermic v. Exothermic

Postby MCalcagnie_ 1D » Sun Jan 31, 2021 9:02 pm

I am pretty sure because of the nature of exothermic and endothermic reactions, exothermic will always be negative and endothermic will always be positive. Exothermic is releasing heat, so the object or substance of interest would be losing heat, with a -delta H. Endothermic is requiring heat, so the object or substance of interest would be gaining heart, with a +delta H.

Presley Gao 2C
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Re: Endothermic v. Exothermic

Postby Presley Gao 2C » Sun Jan 31, 2021 9:11 pm

Yes, endothermic reactions will always have a positive delta H, and yes, exothermic reactions will always have a negative delta H. There are no exceptions to this rule.

Bryan Le 2K
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Re: Endothermic v. Exothermic

Postby Bryan Le 2K » Sun Jan 31, 2021 9:15 pm

Delta H is positive when the reaction is endothermic because heat is absorbed while delta H is negative when the reaction is exothermic because heat is released.

Kelly Ha 1K
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Re: Endothermic v. Exothermic

Postby Kelly Ha 1K » Sun Jan 31, 2021 9:19 pm

Endothermic reactions have a positive delta H because the system is absorbing heat from the surroundings. Exothermic reactions have negative delta H because the system is releasing heat into the surroundings.

Annie Liang 3D
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Re: Endothermic v. Exothermic

Postby Annie Liang 3D » Sun Jan 31, 2021 9:33 pm

Yes, endothermic reactions always have positive delta H values while exothermic reactions will always have a negative delta H value.

Rachel Kho Disc 2G
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Re: Endothermic v. Exothermic

Postby Rachel Kho Disc 2G » Sun Jan 31, 2021 9:50 pm

I'm pretty sure that there will be no exceptions to the fact that delta H is positive and negative for endothermic and exothermic reactions, respectively. Other things to keep in mind when differentiation between the two include:

Endothermic
- energy absorbed
- bonds broken
- strong reactant bonds

Exothermic
- energy released
- bonds formed
- strong product bonds

joshtully
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Re: Endothermic v. Exothermic

Postby joshtully » Sun Jan 31, 2021 11:47 pm

Endothermic reactions has a positive delta H value while exothermic has negative.

RyanKopeikin_2I
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Re: Endothermic v. Exothermic

Postby RyanKopeikin_2I » Tue Feb 02, 2021 5:08 pm

Exothermic reactions will always have negative delta H because heat is being released, which is denoted with a negative sign. Endothermic reactions will always have positive delta H because heat is being absorbed, which is denoted with a plus sign.

Carly_Lipschitz_3H
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Re: Endothermic v. Exothermic

Postby Carly_Lipschitz_3H » Sun Feb 07, 2021 3:32 pm

Yes, you're correct. Exothermic reactions will always have a negative delta H, while endothermic reactions will always have a positive delta H. Endothermic reactions take up energy, making their delta H positive while exothermic reactions give away energy to its surroundings, making their delta H negative.

Mina Tadros 3L
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Re: Endothermic v. Exothermic

Postby Mina Tadros 3L » Sun Feb 07, 2021 3:36 pm

Exothermic reactions are a release in heat and, thus, they have a negative value associated with them. An absorption in energy/heat is an endothermic process, and, therefore, it will always be positive.

Vivian_Le_1L
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Re: Endothermic v. Exothermic

Postby Vivian_Le_1L » Sun Feb 07, 2021 5:01 pm

Endothermic reactions will always have a positive delta H, because they are taking in heat/energy. Exothermic reactions will always have a negative delta H, because they are releasing heat/energy.

Ryan_Kien_1L
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Re: Endothermic v. Exothermic

Postby Ryan_Kien_1L » Sun Feb 07, 2021 5:08 pm

Yes, by definition, I believe positive delta H is endothermic because it's a gain in energy, meaning a positive delta H.

Jose Miguel Conste 3H
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Re: Endothermic v. Exothermic

Postby Jose Miguel Conste 3H » Sun Feb 07, 2021 10:03 pm

That will always be the case as when you have to input energy, delta H has to be positive

Lauren Mungo 1K
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Re: Endothermic v. Exothermic

Postby Lauren Mungo 1K » Sun Feb 07, 2021 10:08 pm

Yes exothermic reaction always have a negative delta H and endothermic reactions have a positive delta H

Karen Zheng_2K
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Re: Endothermic v. Exothermic

Postby Karen Zheng_2K » Sun Feb 07, 2021 10:36 pm

Endo = (+)delta H, and Exo = (-)delta H

John_Tran_3J
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Re: Endothermic v. Exothermic

Postby John_Tran_3J » Sun Feb 07, 2021 10:38 pm

Regarding phases change, when a solid becomes to liquid, heat is NEEDED to melt the solid.. also known as endothermic

Karen Elrayes 1L
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Re: Endothermic v. Exothermic

Postby Karen Elrayes 1L » Sun Feb 07, 2021 10:40 pm

Endothermic means energy went into the system which means delta H increased so it has to be positive. And the opposite is also true.

IshanModiDis2L
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Re: Endothermic v. Exothermic

Postby IshanModiDis2L » Sun Feb 07, 2021 10:44 pm

Yes they will always act this way; exothermic reactions will always be losing heat, meaning that the delta h must be negative and endothermic reactions will always be gaining heat with a positive delta h

rhettfarmer-3H
Posts: 96
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Re: Endothermic v. Exothermic

Postby rhettfarmer-3H » Sun Feb 14, 2021 7:42 pm

Yes, exothermic reactions will always have a negative H. However, if the Recants acclimate then it can become spontaneous which I don't know if that shows more about h or the G.


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