Final answer:
To identify a chemical reaction, you can look for five indicators: a change in color, an energy change (such as temperature change or light production), gas production, formation of a precipitate, and a change in odor.
Step-by-step explanation:
Indicators of a Chemical Reaction
There are several indicators that can signal that a chemical reaction is taking place. Here are five common ones:
- Change in color: This occurs when the reaction leads to a substance with a different color than the reactants.
- Energy change: This can be either a temperature increase or decrease, or light being produced if the reaction is exothermic or endothermic.
- Gas production: Bubbles are formed when a gas is produced at the temperature of the starting materials, which is different from boiling.
- Formation of a precipitate: The creation of a solid product in a reaction that was not initially present is a good indication.
- Change in odor: A new smell indicates that new compounds are being formed during the reaction.
These physical changes are evidence that a chemical reaction might be occurring. Observing these signs can help scientists confirm chemical changes.