If you leave a glass of tap water out long enough, the water will evaporate and leave behind a white solid. Is this a chemical or physical change?
physical change.
To determine whether the process of water leaving behind a white solid when left out is a chemical or physical change, we can consider the following explanation:
A physical change is a change that does not involve a change in the chemical composition or identity of a substance. Examples of physical changes include changes in state (such as melting, freezing, or evaporating) or changes in shape or size.
A chemical change, on the other hand, involves a chemical reaction where new substances with different chemical compositions and properties are formed. Examples of chemical changes include combustion, rusting, or the digestion of food.
In the given scenario, when you leave a glass of tap water out for a long period of time, the water evaporates, leaving behind a white solid. This process is a physical change.
The white solid that remains is likely mineral deposits, such as calcium carbonate or other dissolved minerals in the tap water. These solid particles were already present in the water but were dissolved in it. As the water evaporates, the dissolved minerals are left behind, forming a white residue.
In summary, the process of water evaporating and leaving behind a white solid when left out is a physical change. It involves the change in state of water from liquid to gas, with the solid residue being a result of mineral deposits that were already present in the water.