Chemical Change vs. Physical Change - Chemistry LibreTexts

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3. Analytical Chemistry
4. Qualitative Analysis

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** Chemical Change vs. Physical Change **

1. * Last updated
08:19, 5 Nov 2014

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1. Introduction
2. Common Physical Changes

1. Texture
2. Color
3. Temperature
4. Shape
5. Change of State

3. Physical Properties

1. Luster
2. Malleability
3. Ability to be drawn into a thin wire
4. Density
5. Viscosity

4. Common Chemical Changes

1. Change in Temperature
2. Change in Color
3. Noticeable Odor
4. Formation of a Precipitate
5. Formation of Bubbles

5. References
6. Outside Links
7. Problems
8. Answers
9. Contributors

The difference between a physical reaction and a chemical reaction is
*composition*. In a chemical reaction, there is a change in the composition
of the substances in question; in a physical change there is a difference
in the appearance, smell, or simple display of a sample of matter without a
change in composition. Although we


Source: chem.libretexts.org/Core/Analytical_Chemistry/Qualitative_Analysis/Chemical_Change_vs._Physical_Change


how do you know a physical change has taken place


Physical change - Wikipedia, the free encyclopedia

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** Physical change **

From Wikipedia, the free encyclopedia
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This article *needs additional citations for verification*. Please help
improve this article by adding citations to reliable sources. Unsourced
material may be challenged and removed. /(November 2011)/ /(Learn how and
when to remove this template message)/

*Physical changes* are changes affecting the form of a chemical substance,
but not its chemical composition. Physical changes are used to separate
mixtures into their component compounds, but can not usually be used to
separate compounds into chemical elements or simpler compounds.^[1]

Physical changes occur when objects or substances undergo a change that
does not change their chemical composition. This contrasts with the concept
of chemical change in which the composition of a substance changes or one
or more substances combine or break up to form new substances. In general a
physical change is reversible using physical means. For example, salt
dissolved in water can be recovered by allowing the water to evaporate.

A physical change involves a change in physical properties. Examples of
physical properties include melting, transition to a gas, change of
strength, change of durability, changes to crystal form, textural change,
shape, size, color, volume and density.

An example of a physical change is the process of tempering steel to form a
knife blade. A steel blank is repeatedly heated and hammered which changes
the hardness of the steel, its flexibility and its ability to maintain a
sharp edge.

Many physical changes also involve the rearrangement of atoms most
noticeably in the formation of crystals. Many chemical changes are
irreversible, and many physical changes are reversible, but reversibility
is not a certain criterion for classification. Although chemical changes
may be recognized by an indication such as odor


Source: en.wikipedia.org/wiki/Physical_change

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