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A physical change is one in which alterations arise in their form without the need for the matter to be transformed, that is, their original substances prevail in them. These involve states of matter and energy, creating new forms in the elements.
- A physical change is said to occur when substances mix but do not react chemically.
- These changes can be reverted, however not all changes are easy to revert.
- Its identity remains the same, otherwise we can call it a »chemical change.
One way to identify a physical change is that such a change may be reversible, especially a phase change. For example, if you freeze water in an ice cube, you can melt it back into the water. This can be through observation and measurement, which are one of the most common methods used in science to investigate phenomena, seeking to detect the characteristics of each element using the senses as tools.
On some occasions the transformation can be reversible, by using different techniques to separate its elements and/or reverse the change and return to what were its natural elements »physical change».
Examples of physical changes
Remember that they can visibly change, however, their chemical identity will remain intact. One way to identify if this is a physical change is to rule out the possibility that this is a chemical change, looking for any sign that a chemical reaction has occurred.
The evolution of the processes integrates a transformation, which would be a fundamental piece in the force of change and the evolution of the processes, when the elements are unified and thus create new compounds.
- crush a can
- A melting ice cube
- coffee and sugar
- To cut wood
- crumple up a paper bag
- break a glass
- The mixture of water and oil
- vaporize liquid nitrogen
- Lettuce mixed with pasta in a salad
- Flour, salt and sugar
- Bread with marmalade
Indicators of a Chemical Change
A chemical change implies a transformation of its elements into new compounds, which means that its properties can be transformed into a completely different substance.
Note: One of the main characteristics of chemical changes is the irreversibility of the process, since when their products are transformed they will not be able to return to their original elements.
- Bubble evolution or gas release
- absorb or release heat
- Color change
- release a scent
- Inability to reverse the change
- Precipitation of a solid from a liquid solution
- Formation of a new chemical species.
»This is the most reliable indicator, since a change in the physical properties of the sample can indicate a chemical change»
For example: flammability and oxidation state.
