Final answer:
The yellow diamond on the NFPA 704 symbol indicates reactivity hazard, which represents how readily a substance will undergo detonation or a violent chemical change.
Step-by-step explanation:
The yellow diamond on the NFPA 704 symbol indicates reactivity hazard. It describes how readily the substance will undergo detonation or a violent chemical change.
The Hazard Identification System developed by the National Fire Protection Agency (NFPA) provides safety information about certain substances. The system uses a diamond-shaped symbol with different colored diamonds to represent different types of hazards. The yellow diamond specifically represents reactivity hazards.
For example, a substance with a high reactivity hazard rating may be prone to explosive reactions or dangerous chemical changes when exposed to heat, light, or other factors.