Physical transforms are limited to alters that an outcome in a difference in display without transforming the composition. (source)

e.g. Melt water or dissolving street in water

Chemical reactions are the processes whereby chemicals connect to type new chemicals with various compositions. (source)

e.g. Burning $ceH2$ to $ceH2O$

But what is dissolve salt in water? Is that a physical adjust (like dissolving sugar) or is that a reaction?


I would think that dissolving a non-reactive salt, favor $ceNaCl$ in water can be considered as a physics change. This is because, you can recover the salt through evaporating the water away.

From the Wikipedia web page of physical change

In general a physical adjust is reversible utilizing physical means. For example, salt dissolved in water have the right to be recovered by enabling the water come evaporate.

You are watching: Is dissolving salt in water a chemical or physical change

But the difference between physical and also chemical readjust can be misleading and confusing at times. In general, anything the does not adjust the chemical constitution of the substance, is a physics change.

When girlfriend dissolve $ceNH3$ in water, the adhering to equilibrium is set up:

$$ceNH3 + H2O NH4+ + OH-$$

But if you heat the water up, you will get back the initial ammonia without any kind of chemical change in that composition. However, the ammonia does readjust its chemical composition in water, together $ceNH4+$ ions room formed. By the argument, you have the right to say that the dissolution of an ionizable salt is a change.

In some cases, dissolved of a compound can be referred to as a true chemical reaction. For example, when you dissolve Calcium oxide ($ceCaO$) in water, a vigorous chemical reaction bring away place, developing $ceCa(OH)2$. You can not get earlier the original $ceCaO$ by just evaporating the water. In situation of aqueous equipment of $ceAlCl3$, if you shot to evaporate the water by heater the solution, you will certainly get ago only $ceAl(OH)3$ together anhydrous $ceAlCl3$ reacts through water as quickly as the is in call with water, to kind $ceAl6Cl3$.

What ns am trying to say is the some transforms can it is in classified into one of this types, while some other alters can not be given a clean classification. Melt of water is plainly a physical change, when reaction that $ceH2$ and also $ceO2$ is clearly a chemical change. One one more fact, putting repaint on a canvas is not constantly a physics change. In truth some paints are manufactured in such a way that throughout drying, some chemical reaction occur, as result of which the paint fixes firmly on the surface. This is the reason many water thinnable paints have the right to not be dissolved in water as soon as they end up being dry.

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To conclude, you should not hold tough classifications choose that in her mind. However, my final verdict: dissolving a salt is physical readjust (mostly).