which sign of chemical reaction is not detectable by sight?
The sign of a chemical reaction that is not detectable by sight refers to a type of evidence that cannot be observed with the naked eye. In this case, the sign is known as a chemical change. Chemical changes involve the rearrangement of atoms and the formation of new substances, resulting in a different chemical composition.
Although some chemical changes may produce observable signs, such as changes in color, the formation of a precipitate, or the emission of light or gas, there are instances where the signs are not visible. These signs typically require additional tools or tests to be detected. Here are a few examples of signs of chemical reactions that are not readily visible:
1. Temperature Change: A chemical reaction might cause a noticeable change in temperature, either an increase or decrease, indicating that a reaction has occurred. However, this change may not be visible to the naked eye and can only be detected using a thermometer or another temperature-measuring device.
2. Change in Odor: Certain chemical reactions may produce new substances with distinct odors. However, these odor changes may be subtle and not easily detected without using your sense of smell.
3. Formation of New Substances: The most fundamental sign of a chemical reaction is the formation of new substances with different properties. However, these changes are often not visually apparent. To detect the formation of new substances, you might need to perform additional tests, such as chemical analysis or spectroscopy.
In summary, the sign of a chemical reaction that is not detectable by sight refers to evidence that cannot be observed directly. These signs might include temperature changes, odor changes, or the formation of new substances, which require specialized tools or testing methods to be detected.