Harper College explains that forming a precipitate, color changes, gas formation and temperature change are signs of a chemical change. The University of California, Davis adds that the presence of odor also indicates a chemical change. There are only five indicators of a chemical change.Know More
The University of California, Davis explains the a change in temperature is a clear indicator that a chemical change has occurred. Heat is a product of the reaction and is called an exothermic reaction.
Harper College states that when a gas forms after two substances have been combined, it is clear that a chemical reaction has occurred. The gas is a product of the reaction.
If two chemicals are combined and a new color forms, then a chemical reaction has occurred. Harper College explains that this indicates a chemical change as long as the color change is not a result of a dilution.
The University of California, Davis explains that the presence of an odor indicates a chemical change. For example, when an egg begins to smell, a change in the chemical composition of the egg has occurred.
A precipitate indicates a chemical change. Harper College states that a precipitate forms when two substances react together to form a new substance.Learn more in Chemistry
The formation of rust represents a chemical change. When a chemical change occurs, the substance or substances present at the beginning are no longer present at the end of the change. Once a chemical change occurs, it theoretically cannot be undone.Full Answer >
Tarnishing is a chemical change that occurs when certain metals are exposed to air or other sources. The change, known as oxidation reaction, is what leaves behind the tarnish.Full Answer >
Frying an egg involves a chemical change. The heat in the frying process gives energy to the egg's molecules and brings about a permanent change in the substance.Full Answer >
A burning candle is an example of a chemical change because the paraffin wax, which is a hydrocarbon, undergoes a chemical reaction with oxygen to form water and carbon dioxide gas. Because the chemical structure of the paraffin has been altered, this is a chemical change.Full Answer >