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This is a common misconception. Chemical changes can be reversed. It happens all the time, and there's a large branch of physical chemistry devoted to it. The problem stems from some teachers trying to oversimplify when teaching the difference between physical and chemical changes. A chemical change is one which produces a new substance, and a physical change is one which does not. Common examples of physical changes are melting and boiling water, and common examples of chemical changes are rusting and burning. Unfortunately, people extrapolate from these limited examples and their own limited knowledge, to say that since melting and boiling water is easy to reverse, and they don't know how to reverse rusting and burning, that 'chemical changes can't be reversed and physical ones can'. It just isn't true.
When we convert iron to steel, rusty scrap iron is often included in the mixture, and one of the reactions taking place in the converter vessel is the reduction of rust to iron. Burning isn't simple to reverse, not least because the products are usually carbon dioxide and water vapour which escape into the air. However, when plants photosynthesise they take carbon dioxide and water and convert them to glucose and oxygen, and eventually most fuels derive from that glucose. Additionally, not all physical changes are easy to reverse. If you freeze water you can easily turn it liquid again, true, but if you freeze liquid iron you have to heat it to 1538 degrees C to remelt it - hardly easy!
What else can I help you with?
What type of change is striking a match?
Striking a match is a physical change because it can be reversed by extinguishing the flame. The chemical composition of the match does not change during this process.
Is evaporation of spirit on the skin a physical change?
Yes, evaporation of spirit on the skin is a physical change. It is a phase change where the liquid spirit changes into a gas without any chemical reaction occurring. The process can be reversed by condensation.
How is a physical change different than a chemical change?
A physical change is different than a chemical change, because in a physical change, the composition of the matter did not change. While in a chemical change, the composition of the matter did change.SO basically, the composition of the matter does not change is the difference between a physical change and a chemical change.yes
What is a chemical and physical change?
Physical change - a change in a substance that does not involve a change in the identity, including a change in state between solid, liquid and gas phases.Chemical change - a change which one or more substances are converted into different substances, some indications are burning, rusting, color changes etc.physical change can be changedbut in chemical change chemicals are mixed togetherfor example if we are sick that is a physical changewe have to change healthy as wellwhen we mix salt in a dish,can we take out that again?neverthis is chemical changeA physical change is when the object undergoes a change that can be reversed, such as mixing water with salt, melting ice, or freezing or vaporizing water. A chemical change is a change that changes a substance into something else entirely, and therefore cannot be reversed. Examples would be mixing vinegar and baking soda or turning batter into bread.chemical change is when during a chemical reaction a new substance will be formed while in physical change no new substances are formed
How are physical and chemical changes different in two ways?
Physical changes involve alterations in the form or state of a substance without changing its chemical composition. Chemical changes, on the other hand, result in the formation of new substances with different chemical compositions. Physical changes are typically reversible, while chemical changes are often irreversible.
Why cant a chemical reaction be put back the same?
cause chemical reactions cant be reversed
Is baked bread a chemical change?
Yes it is because the chemical properties change and it cannot be reversed.
How tyo recgonize chemical and physical change?
think if it can be reversed. if it is easially reversed, it is most likely physical. ie. if you bake a cake, you cant make it go back to a batter, so it is a chemical change. if you freeze an ice cube, you can just melt it and it goes back to water, so its a physical change.
Is rusting a phsyical change?
Rusting is a chemical change because under it iron goes under oxidation and oxidation is a chemical process. Also, a physical change can be reversed but a chemical change cannot and rusting cannot be reversed. Hence also rusting is a chemical change.
Burning is what form of change?
it is a chemical change because it cannot be reversed
Why is a firework an example of a chemical change in a fourth grade answer?
A chemical change can not be reversed. Obviously the fire work can not be put back together because it has reacted, not being able to be reversed, and therefore, being classified as a chemical change.
Is an egg a chemical change?
Yes, it is, because it cannot be reversed.
Is a given change a chemical or a physical change?
It depends. Physical can be easily reversed. Chemical is hard, if not impossible to reverse.
Is Boiling water is a chemical change?
No, it is a physical change because the water is the same but just boiled
What is the difference between physically and chemical changes?
A chemical change is when something cannot be reversed and often a precipitate (solid) is formed. While a physical change can be reversed e.g bending a piece of wire.
Is cooking egg whites a chemical change?
yes, a chemical change is anything that cannot be reversed, you cannot uncook an egg!
When an egg is cooked is this a physical change?
Cooking an egg is a chemical change because it cannot be reversed.
