Question

explain about physical changes in 25 lines.

Answer 1

Definition of Physical Changes

Substances often undergo changes that make them have a dramatically different appearance, even though the chemical composition of the substance remains unchanged. For example, you can take a flat, smooth sheet of paper and crumple it into a ball or fold it into an airplane. While it may look very different in these three forms, it is still paper. A change like this, which alters a substance's appearance without changing its chemical composition, is known as a physical change.

Properties and Examples of Physical Changes

Physical changes involve changing the physical properties of a substance. Some examples of physical properties include color, volume, shape, and phase changes.

Let's begin by using water as an example. If we have water at room temperature, it is a clear liquid. If we lower the temperature below the freezing point, we have solid ice. If we raise the temperature above the boiling point, we will have gaseous steam. However, do any of these processes change the chemical composition of the water? No. In all three forms, the water is still composed of two hydrogen atoms bonded to one oxygen atom. No other atoms are added or subtracted, so the chemical composition stays the same. The change from liquid to solid or gas is an example of a physical change.

In nature, many elements and compounds naturally undergo the process of crystallization. This means, based on the conditions where they exist, such as temperature and pressure, they form crystals. A common example of this is the element carbon. When carbon is exposed to varying and extreme pressures, it can transform into diamonds, graphite, or a form known as fullerene.

Answer 2

Answer:

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