Science, asked by Aakash2818, 2 months ago

Possible and irreversible are two different things reversible are things that you can DO and UNDO. Irreversible now things you can do but CANNOT undo. EXAMPLE : IRREVERSIBLE Egg you try it but can't unfry the egg EXAMPLE 2 : REVERSIBLE Ice when it melt it becomes liquid but when it freeze again it's becomes ice.

Answers

Answered by pradyumna19092009
0

Answer:

Physical changes involve states of matter and energy. No new substance is created during a physical change, although the matter takes a different form. The size, shape, and color of matter may change. Physical changes occur when substances are mixed but don't chemically react.

How to Identify a Physical 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 into an ice cube, you can melt it into the water again. Ask yourself:

Is the change reversible? Not all physical changes are easy to reverse.

Was there a color change (with exceptions), bubble formation, or formation of a precipitate? These are all signs of a chemical change, not a physical change.

Is the chemical identity of the end product the same as it was before the change? If the answer is yes, it's a physical change. If the answer is no, it's a chemical change.

Examples of Physical Changes

Remember, the appearance of matter changes in a physical change, but its chemical identity remains the same.

Crushing a can

Melting an ice cube

Boiling water

Mixing sand and water

Breaking a glass

Dissolving sugar and water

Shredding paper

Chopping wood

Mixing red and green marbles

Sublimation of dry ice

Crumpling a paper bag

Melting solid sulfur into liquid sulfur. This is an interesting example since the state change does cause a color change, even though the chemical composition is the same before and after the change. Several nonmetals, such as oxygen and radon, change color as they change phase.

Chopping an apple

Mixing salt and sand

Filling a candy bowl with different candies

Vaporizing liquid nitrogen

Mixing flour, salt, and sugar

Mixing water and oil

Indications of a Chemical Change

Sometimes the easiest way to identify a physical change is to rule out the possibility of a chemical change. There may be several indications that a chemical reaction has occurred. Note: It's possible for a substance to change color or temperature during a physical change.

Evolving bubbles or releasing gas

Absorbing or releasing heat

Changing color

Releasing an odor

Inability to reverse the change

Precipitation of a solid from a liquid solution

Formation of a new chemical species. This is the best and surest indicator. A change in the chemical properties of the sample may indicate a chemical change (e.g., flammability, oxidation state).

Explanation:

Similar questions