Question

Identify Indicators of Chemical Changes.

a) Change in color
b) Formation of gas bubbles
c) Formation of a precipitate
d) Change in temperature
e) Change in odor

Answer 1

Chemical changes can be identified through various observable indicators, such as color change, formation of gas bubbles, formation of a precipitate, temperature change, and change in odor.

Step-by-step explanation:

Observations that help to indicate chemical change include:

• Change in color: When the color of a substance changes, it can indicate a chemical change. For example, when iron rusts, it changes from a shiny silver color to a reddish-brown color.
• Formation of gas bubbles: If gas bubbles are produced during a reaction, it suggests a chemical change is occurring. For instance, when vinegar is mixed with baking soda, it produces carbon dioxide gas bubbles.
• Formation of a precipitate: When a solid substance forms during a reaction, it is called a precipitate. This can be an indication of a chemical change. An example is when silver nitrate reacts with sodium chloride to form a white precipitate of silver chloride.
• Change in temperature: A noticeable change in temperature, either an increase or decrease, can signify a chemical change. A common example is the combustion of wood, which produces heat.
• Change in odor: Sometimes, a chemical change can cause a substance to emit a different odor. This change in smell can be an indication of a chemical reaction taking place.