Physical change vs Chemical Change
Change is change; so why do you have to bother with physical or chemical changes. Change occurs in both processes, right? However, there are several differences between physical and chemical change. And it is important to identify them in order to better understand the state of matter or substance.
First of all, when physical change occurs in a substance, you will not be able to create a new substance. The substance will remain in its original state. In contrast, when chemical change occurs in the substance, you will be able to produce a different kind of substance. This means you will lose the original substance and a new one will form.
Based on this premise, any physical change that occurs in matter or substance is completely reversible. But when a chemical change happens, you will not be able to reverse or undo the transformation. For example, water can freeze so liquid can turn to solid but the substance is still water. You can unfreeze ice to revert to the liquid state of water. But if you burn paper, you will get a new substance called ash. You can not ‘un-burn’ ash to transform it back to paper.
Another big difference between physical and chemical change is the speed of transformation. Physical change occurs faster and sometimes instantaneously. Most chemical changes, on the other hand, take longer time to become discernible. You can crumple a tin can and you will immediately see physical changes. But corrosion of tin can occurs very slowly; it will take a long time before you see the appearance of rust on the can.
There is a wide difference between physical and chemical changes. With physical change, you are not transforming the original molecular composition of the substance. But with chemical change, the molecular structure is being transformed thus you will get a new substance.