4a what event is occuring? 4b circle chemical change or physical change liquid a 25℃ liquid b 25℃ 7a what…
4a what event is occuring? 4b circle chemical change or physical change liquid a 25℃ liquid b 25℃ 7a what event is occuring? 7b circle chemical change or physical change
Answer
Explanation:
Step1: Analyze the reaction
Two liquids at 25°C are combined and the resulting mixture has a temperature of 60°C and gas (H₂) is produced. A chemical reaction is occurring as new substances are formed and there is a temperature - change indicating an energy change associated with chemical bond - breaking and forming.
Step2: Determine the type of change
Since a new substance (hydrogen gas) is formed and there is an energy change (temperature increase), this is a chemical change. Physical changes do not result in the formation of new substances.
Answer:
7a. A chemical reaction is occurring. 7b. Chemical Change