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Nick tringali
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Are the laws of conservation of mass always obeyed. in a nuclear reaction mass is converted to energy therefore mass isn't conserved. I understand that energy is always conserved, but I feel like mass isn't.
Since you just stated, correctly that in a nuclear reaction mass is converted to energy, why do you "feel" that mass isn't conserved rather than "know" that mass isn't conserved? What IS conserved in a nuclear reaction?Nick tringali said:Are the laws of conservation of mass always obeyed. in a nuclear reaction mass is converted to energy therefore mass isn't conserved. I understand that energy is always conserved, but I feel like mass isn't.
@dRic2, on PF we try to help people figure out how to get answers for themselves rather than just giving them the answers.dRic2 said:I'm totally ignorant about nuclear reaction, but I know conservation of mass/energy in nuclear reaction follows the rule ##E = mc^2##. If you lose some mass you have to gain an equal amount of energy and vice versa. (very brutally said)
phinds said:@dRic2, on PF we try to help people figure out how to get answers for themselves rather than just giving them the answers.
Sure. I understand that you were being helpful and I applaud that. I was just concerned that your hint was more like an answer. I was trying to get him to think about it. You are right that he basically already HAD the answer he just didn't seem to have thought it through.dRic2 said:I'm very sorry, I thought the OP got a little confused but wasn't far from the explanation. I meant the answer as a hint to find other material online because, as I said, I don't know much more about it.
Google is your friendNick tringali said:yes, so mass isn't conserved. Energy is, but then why is the "Law of conservation of mass" a thing.
In education, the process is first you learn to crawl, then walk, then run. One does not start out teaching Quantum Mechanics and General Relativity.Nick tringali said:I'm looking for more of a definitive answer as to if the law of conservation is not obeyed all the time, then why does education make it seem that it is always obeyed and mass is always conserved. Thanks anyways.
Yes. When it is converted to mass.Nick tringali said:since we are on this topic, is there any time that energy isn't conserved.
As with everything, conservation of energy has limits to its applications as well. However, those details are probably best left until A-level general relativity ... In the meantime, you can consider energy as conserved.Nick tringali said:However, energy is always conserved in every way shape and form.
Well ... I do not believe this is a constructive way of looking at things. The natural interpretation is that mass is a form of energy and that non-conservation of mass is just conversion of mass into other forms of energy.phinds said:Yes. When it is converted to mass.
Nick tringali said:Are the laws of conservation of mass always obeyed.
nikkkom said:another common (maybe even most common now) use of term "mass" is that mass is the length of 4-momentum vector of Special Relativity: m^2 = E^2 + p^2.
jartsa said:A: The change of the the energy of the car depends on the frame. B: The mass of the car decreases.
So mass of the car is not conserved, and neither is the energy of the car.
The energy of the car is not conserved in all frames.nikkkom said:Incorrect. Energy, of course, is frame-dependent. This does not invalidate energy conservation.
Car's energy is likely not conserved since it's not a closed system - it pushes against the Earth, the radiation and heat is escaping the car, etc.
In which frame is the energy conservation violated?jartsa said:The energy of the car is not conserved in all frames.
ChrisVer said:In which frame is the energy conservation violated?
f todd baker said:The simple fact is that there is no such thing as conservation of mass.
f todd baker said:In a chemical reaction, burning something for example, the thermal energy after the burning is the result of the initial mass becoming smaller.
The law of conservation of mass states that matter cannot be created or destroyed, it can only change forms. This means that in any chemical reaction, the total mass of the reactants must be equal to the total mass of the products.
The law of conservation of mass was first proposed by Antoine Lavoisier, a French chemist, in the late 18th century. He conducted experiments and observations on the combustion of substances and concluded that mass is conserved in chemical reactions.
The law of conservation of mass is closely related to the atomic theory, which states that all matter is composed of tiny particles called atoms. The law of conservation of mass can be explained by the fact that atoms are neither created nor destroyed in a chemical reaction, they simply rearrange to form new substances.
In most cases, the law of conservation of mass holds true. However, there are a few exceptions such as nuclear reactions, where a small amount of mass can be converted into energy according to Einstein's famous equation E=mc². Additionally, in some chemical reactions, a small amount of mass may be lost due to the formation of gases or other substances that escape the reaction vessel.
The law of conservation of mass is a fundamental principle in chemistry and is essential for understanding and predicting chemical reactions. It allows scientists to accurately measure the mass of reactants and products and ensures that the total amount of matter in a system remains constant. This law also helps to explain many natural phenomena, such as the water cycle and the carbon cycle, which involve the conversion of matter from one form to another.