Where Does The Loss of Mass Occur When an Exothermic Reaction Occurs?

[dr.syntax]

It is my understanding that any reaction that generates energy, both chemical and nuclear reactions result in the loss of some mass. That exactly the same E=MC2 ratio of energy to loss of mass occurs in both types of reactions. I know every atom along with their electrons is accounted for in all chemical reactions. So in an exothermic reaction how is this loss of mass accounted for be they chemical or nuclear. Also when endothermic reactions occur, do they result in a gain in mass ? Do the subatomic particles get less massive in some way when exothermic reactions take place ? And do they get more massive when endothermic reactions take place. I have often wondered about this, can someone out there answer these related questions. Thank You, ...Dr.Syntax

Edited October 30, 2009 by dr.syntax
word left out

[ydoaPs]

Heat and/or photons.

[swansont]

The individual particles' masses are always given in an unbound state. Once they form a bound system, you can't really talk about the individual masses. The system gains or loses mass. In the case of e.g. a hydrogen atom, it loses the mass equivalent of 13.6 eV when a proton combines with an electron, and it drops into the ground state.

[dr.syntax]

The individual particles' masses are always given in an unbound state. Once they form a bound system, you can't really talk about the individual masses. The system gains or loses mass. In the case of e.g. a hydrogen atom, it loses the mass equivalent of 13.6 eV when a proton combines with an electron, and it drops into the ground state.

 

REPLY: I am no physicist, when you say a proton combines with an electron are you describing the creation of a neutron or do you mean a proton combines with an electron to create a hydrogen atom ? I appreciate your help with this. ...Dr.Syntax

[DrP]

It's both physics and chemistry at the same time - quantum mechanics. When an electron in an exited state in the hydrogen atom (or any atom or molecue) drops to a lower energy level, the energy is emited as an electromagnetic wave. As you stated - E = MC^2

[dr.syntax]

Heat and/or photons.

 

REPLY: I was not clear in my question. I will stick with only one question. Unless I totally misunderstand it all : Some mass is lost in say the oxidation of H2. 2 H2+1 O2 = 2 H2O and heat or photons,energy. So what loses mass ? E=MC2 says some mass is lost because some energy is emitted . What loses mass ? The protons ? The neutrons of the oxygen atoms ? The electrons ? Energy is emitted therefore some mass is lost. I appreciate your interest. ...Dr.Syntax

---

Merged post follows:

Consecutive posts merged

REPLY: This is what some of the different wikipedia articles say :

1.mass and energy are the same thing

2.when energy leaves a system it takes it`s mass with it

3.kinetic energy can be converted to particles that have mass

 

I think I am starting to understand all this, starting to only. Dr. Syntax

Edited October 30, 2009 by dr.syntax
Consecutive posts merged.

[insane_alien]

and H2+O2 mixture has a higher energy state than H2O when the bonds are reconfigured to the lower energy state of H2O this energy is released and hence mass.

 

before the energy is released it is in the form of potential energy.

 

it is a ridiculously small amount of mass lost though. 5.3ng per mole of water produced or 0.294ng per gram of water produced.

[dr.syntax]

and H2+O2 mixture has a higher energy state than H2O when the bonds are reconfigured to the lower energy state of H2O this energy is released and hence mass.

 

before the energy is released it is in the form of potential energy.

 

it is a ridiculously small amount of mass lost though. 5.3ng per mole of water produced or 0.294ng per gram of water produced.

 

REPLY: But I also learned from some different wiki articles that mass is a confined form of energy. When energy leaves a system it takes it`s mass with it just as E=MC2 says it does. Also, kinetic energy can be converted to particles that have mass. Need some sleep. ...Dr.Syntax

[insane_alien]

i don't see how that merits a 'but'. there isn't anything incompatible.

 

i suspect that you may be confusing matter and mass.

[swansont]

REPLY: I am no physicist, when you say a proton combines with an electron are you describing the creation of a neutron or do you mean a proton combines with an electron to create a hydrogen atom ? I appreciate your help with this. ...Dr.Syntax

 

A hydrogen atom is an electron bound to a proton. The mass of a free electron + free proton is greater than the mass of a hydrogen atom, by about 0.00055 atomic mass units

[dr.syntax]

i don't see how that merits a 'but'. there isn't anything incompatible.

 

i suspect that you may be confusing matter and mass.

 

REPLY: You are right as usual. I guess from reading the different wiki articles I finally GOT IT. I read a lot of them. They made it clear to me. Energy and matter are the same thing. Matter is a confined form of energy.When energy leaves a system it takes it`s mass with it in the ratio given in E=MC2. I never said you were wrong about anything. I guess the BUT meant the way it was worded made me finally understand what for some reason I never quite grasped before. If I offended you I am sorry. I see how you would be though that was not my intention I ASSURE you. Thanks to you I was spared a good deal of humiliation yesterday. Try not to be too tough on me, I am very tired. Now you take care , ...Dr.Syntax

[swansont]

REPLY: You are right as usual. I guess from reading the different wiki articles I finally GOT IT. I read a lot of them. They made it clear to me. Energy and matter are the same thing. Matter is a confined form of energy.When energy leaves a system it takes it`s mass with it in the ratio given in E=MC2. I never said you were wrong about anything. I guess the BUT meant the way it was worded made me finally understand what for some reason I never quite grasped before. If I offended you I am sorry. I see how you would be though that was not my intention I ASSURE you. Thanks to you I was spared a good deal of humiliation yesterday. Try not to be too tough on me, I am very tired. Now you take care , ...Dr.Syntax

 

No, energy and matter are not the same thing. Mass and matter are not the same thing. Mass and energy are properties matter can have.

 

Energy and mass are interchangeable.

[dr.syntax]

No, energy and matter are not the same thing. Mass and matter are not the same thing. Mass and energy are properties matter can have.

 

Energy and mass are interchangeable.

 

REPLY: That`s your opinion. Among the different wiki articles I read it was stated that matter is confined energy. Any that when any given amount of energy leaves that system it takes it`s mass along with it as in the ratio given in E=MC2. This is what made it possible to grasp what all this E=MC2 stuff is all about. Am I not allowed to have an opinion that is different than yours ? Is that against the rules here. If it is let me know and I will have to come to a decision inside myself as to whether it is worth it to me or not to be a member here. I like this forum a lot. I`ve made some good friends here and such. I don`t know what to say. I am not going to get drawn into another war here,so to speak. They make me very unhappy. ...Dr.Syntax ... P.S. I just reread your post and am not sure we disagree about anything. I have never come to grips with all of this concept. And am making my first steps inside my mind toward understanding it. I will do some more web searches concerning the difference between mass and matter for one thing. Sincerely, Dr.Syntax

---

Merged post follows:

Consecutive posts merged

REPLY: That`s your opinion. Among the different wiki articles I read it was stated that matter is confined energy. Any that when any given amount of energy leaves that system it takes it`s mass along with it as in the ratio given in E=MC2. This is what made it possible to grasp what all this E=MC2 stuff is all about. Am I not allowed to have an opinion that is different than yours ? Is that against the rules here. If it is let me know and I will have to come to a decision inside myself as to whether it is worth it to me or not to be a member here. I like this forum a lot. I`ve made some good friends here and such. I don`t know what to say. I am not going to get drawn into another war here,so to speak. They make me very unhappy. ...Dr.Syntax ... P.S. I just reread your post and am not sure we disagree about anything. I have never come to grips with all of this concept. And am making my first steps inside my mind toward understanding it. I will do some more web searches concerning the difference between mass and matter for one thing. Sincerely, Dr.Syntax

 

REPLY:Here is an explanation wiki answers . com provided :quote " A useful distinction between mass and matter can be described in the following way. Let`s use the mouse trap as an example. If I set the mousetrap it has more mass due to the energy I have put into it. E/C^2=M .

 

So the mass has increased,but it still has the same amount of fundamental " matter" particles. [ electrons and quarks ]" unquote. So does this agree with your interpretation of the difference in matter and mass or not ? I would say that it adds to my recently acquired concept of what mass/ matter/ energy is. ...Dr.Syntax ... The web address for this is: [ http://wiki.answers.com/Q/How_is_mass_and_matter_different ].

Edited October 31, 2009 by dr.syntax
Consecutive posts merged.

[Mr Skeptic]

I just call it mass-energy.

[dr.syntax]

and H2+O2 mixture has a higher energy state than H2O when the bonds are reconfigured to the lower energy state of H2O this energy is released and hence mass.

 

before the energy is released it is in the form of potential energy.

 

it is a ridiculously small amount of mass lost though. 5.3ng per mole of water produced or 0.294ng per gram of water produced.

 

REPLY: The one thing I noticed going through this thread is that no one answered the questions which I reduced to one question in hopes of allaying any further confusion. That question is: What exactly becomes less massive when energy departs a system along with it`s mass as quantified in the equation E=MC^2 ? You state it is a ridiculously small amount. Never the less, some mass is lost. Now, consider the 14 billion years or so that this Universe has been in existence and how many times some of these atoms or their subatomic particles may have been recycled. It still may not amount to that much mass being lost.I do not know. I can imagine a highly skilled mathematician could come up with a fairly accurate amount of mass loss for say the hydrogen atoms and carbon atoms here on the surface of the earth and it`s atmosphere. Which goes to one of the original questions of this thread : Do endothermic reactions such as those associated with photo synthesis gain mass. It seems to me they would gain mass. So where is all this mass exchange going on ? Are the different sub atomic particles becoming less massive during exothermic reactions ? Let`s stick with that one question unless some one would like to answer both. What becomes less massive when energy departs a system with it`s mass as described by E=MC^2 ? During exothermic chemical reactions I presume,perhaps wrongly, that all the atoms and ions and their electrons do not disappear. I have not run across anything yet that says exactly where this mass loss occurs. Don`t just get mad at me because I don`t toady up to you. You Friend, Dr.Syntax

---

Merged post follows:

Consecutive posts merged

It is my understanding that any reaction that generates energy, both chemical and nuclear reactions result in the loss of some mass. That exactly the same E=MC2 ratio of energy to loss of mass occurs in both types of reactions. I know every atom along with their electrons is accounted for in all chemical reactions. So in an exothermic reaction how is this loss of mass accounted for be they chemical or nuclear. Also when endothermic reactions occur, do they result in a gain in mass ? Do the subatomic particles get less massive in some way when exothermic reactions take place ? And do they get more massive when endothermic reactions take place. I have often wondered about this, can someone out there answer these related questions. Thank You, ...Dr.Syntax

 

REPLY: Is there any measurable difference in the mass of the CARBON,HYDROGEN,and OXYGEN Atoms that have been actively involved in a wide variety of chemical reactions since the emergence of photosynthesis here on the planet Earth for about 3 billion years now.Of course this would also include those chemical reactions that transpired in all the different organisms that make use of those three different elements in their live`s metabolism. No matter how small the loss of mass due to the departure of mass that accompanies any exothermic chemical reaction is, it would seem to me that there would be a measurable difference due to the accumulative effect over those three billion years.

Also, there may have been an overall increase in the mass of these atoms because of the overall endothermic result of these chemical reactions. This seems to me the most likely overall result of the chemical reactions involved in the life processes that occur on Earth. After all, is that not the net result of photosynthesis,the substantial gain and storage of energy

during this process. Is that not what all these fossil fuels are ? A net gain of energy in at least the carbon and hydrogen,hydrocarbon molecules that make up the different hydrocarbons stored in the Earth ?

So, are the carbon,hydrogen,and perhaps oxygen atoms measurably more massive than those same elements that have not been involved in life processes ? Are these questions already answered ? Are there any water samples to examine from the moon or Mars or from some comet ? I don`t know, do you ? ...Dr.Syntax

Edited October 31, 2009 by dr.syntax
Consecutive posts merged.

[swansont]

REPLY: The one thing I noticed going through this thread is that no one answered the questions which I reduced to one question in hopes of allaying any further confusion. That question is: What exactly becomes less massive when energy departs a system along with it`s mass as quantified in the equation E=MC^2 ?

 

I answered it in post #3. The system, as a whole, loses the mass. The mass of individual particles is known for an unbound state only — once you combine them, you can't tell what their individual masses are.

[dr.syntax]

Samples including water and amino acids were retrieved from a comet and returned to Earth in 2006. So, someone with access to those samples measure the masses of those three elements, carbon,hydrogen, and oxygen`s atomic masses and get back me ASAP : ...Dr.Syntax

---

Merged post follows:

Consecutive posts merged

I answered it in post #3. The system, as a whole, loses the mass. The mass of individual particles is known for an unbound state only — once you combine them, you can't tell what their individual masses are.

 

REPLY: Are the atoms the system ? If not,what is ? ...Dr.Syntax

Edited October 31, 2009 by dr.syntax

[Mr Skeptic]

What exactly becomes less massive when energy departs a system along with it`s mass as quantified in the equation E=MC^2 ?

 

The system as a whole loses mass-energy.

 

REPLY: Is there any measurable difference in the mass of the CARBON,HYDROGEN,and OXYGEN Atoms that have been actively involved in a wide variety of chemical reactions since the emergence of photosynthesis here on the planet Earth for about 3 billion years now.

 

No, it doesn't work that way. When you release energy by combining C with O2 to get CO2, what you have is CO2. If you want to get the C and O2 back, you have to put the energy back to break the bonds. The energy used to make and break bonds is exactly equal, so a net zero result.

---

Merged post follows:

Consecutive posts merged

I answered it in post #3. The system, as a whole, loses the mass. The mass of individual particles is known for an unbound state only — once you combine them, you can't tell what their individual masses are.

 

So how did they measure the masses of quarks then? They threw electrons at them, no? But if you do that do you get the mass of an unbound quark?

[insane_alien]

actually for quarks they looked at the different compinations of quarks(not just protons and neutrons) and done some fancy mathematics to derive the unbound mass algebraicly.

[dr.syntax]

A hydrogen atom is an electron bound to a proton. The mass of a free electron + free proton is greater than the mass of a hydrogen atom, by about 0.00055 atomic mass units

 

REPLY: Thank you, you a very clear on you what you mean. So, does that not mean that the mass of the different atoms becomes somewhat smaller during exothermic chemical reactions ? The atom as a whole so to speak. ...Dr.Syntax

[swansont]

So how did they measure the masses of quarks then? They threw electrons at them, no? But if you do that do you get the mass of an unbound quark?

 

No such thing as an unbound quark. AFAIK this is a reason why the masses are not well-known, as compared to the masses of other particles.

[Brzusa]

I had the same thought today regarding mass loss of chemical reactions and after finding your thread on google I decided to sign up to share my thoughts.

 

Lets consider a simple reaction such as CH4 + 2O2 -> CO2 + 2H2O

We are often taught that the mass is conservative as all particles are accounted for, but what if the mass (as has been stated earlier in this forum) changes for the electrons in different potentials throughout the orbitals?

 

Since energy is mass, that could account for the mass difference in chemical reactions. Higher energy electrons are more massive and when stabilized in a lower energy bond, release their a part of their "mass".

 

 

I thought about how to prove such and idea and thought about JJ Thompson's experiment and the LHC:

Imagine applying an electric potential an atom and removing the furthermost electron as JJ thompson did in his experiments you can now measure the mass of this electron as a beam.

We now for a fact that electrons become more massive as they gain Kinetic energy (accelerating them to close to the speed of light as is done in the large hadron collider).

 

Since potential and kinetic energies are usually interchangeable consider the electron's mass to be proportionate to the potential energies of the nucleus.

 

 

Lets now imagine that the possibility of weighing a single electron within different orbitals of the carbon atom. The inner most electrons would weigh less than those farthest from the nucleus.

 

Thank you for reading my thoughts.

 

[swansont]

I had the same thought today regarding mass loss of chemical reactions and after finding your thread on google I decided to sign up to share my thoughts.

 

Lets consider a simple reaction such as CH4 + 2O2 -> CO2 + 2H2O

We are often taught that the mass is conservative as all particles are accounted for, but what if the mass (as has been stated earlier in this forum) changes for the electrons in different potentials throughout the orbitals?

 

Since energy is mass, that could account for the mass difference in chemical reactions. Higher energy electrons are more massive and when stabilized in a lower energy bond, release their a part of their "mass".

 

 

I thought about how to prove such and idea and thought about JJ Thompson's experiment and the LHC:

Imagine applying an electric potential an atom and removing the furthermost electron as JJ thompson did in his experiments you can now measure the mass of this electron as a beam.

We now for a fact that electrons become more massive as they gain Kinetic energy (accelerating them to close to the speed of light as is done in the large hadron collider).

 

Since potential and kinetic energies are usually interchangeable consider the electron's mass to be proportionate to the potential energies of the nucleus.

 

 

Lets now imagine that the possibility of weighing a single electron within different orbitals of the carbon atom. The inner most electrons would weigh less than those farthest from the nucleus.

 

Thank you for reading my thoughts.

The mass of the more tightly-bound system will be lower, but by only a few eV. For the accounting in a chemical reaction, this mass is not measurable, so it is typically ignored.

[joemorin]

Pretty lame for me to comment on a 6 year old discussion, but I found myself asking the same question Dr. Syntax was asking and then realized that no one really answered the question. Here is my take: In an exothermic chemical reaction mass can be "lost" in two different ways: One way is in the form of photons leaving the system as radiation created when electrons change energy levels. Secondly, exothermic reactions can also lose heat (and yes relativistic mass) through conduction, convection and advection which all result in a loss of mass in reactants as the atoms of the reactants lose kinetic energy and transfer that energy to their immediate environments as heat--this type of heat exchange excites the atoms of adjoining matter outside of the reaction increasing the kinetic energy of those atoms outside of the reaction. Thus, the lowered total kinetic energy of atoms of the reactants (becoming a product) results in lowered total mass of those atoms, and the higher kinetic energy of the atoms outside of the reaction results in higher mass of those atoms---as we know that a particle's mass (relativistic mass) changes with its velocity.

[hoola]

I saw AJB say that the mass of a free electron + free proton is larger than that of a hydrogen atom....why is that?

Edited December 5, 2015 by hoola