🔍 Key Concepts

• Flash point vs. ignition temperature – know the difference between the temperature where a liquid gives off enough vapor to ignite (flash point) and where it will self-ignite without a spark (auto‑ignition). • U.S. Coast Guard liquid grade classifications (A–E) – how grades change as flash point goes up and volatility goes down. • Characteristics of heavy fuel oils (e.g., Bunker C) – thick, high‑flash‑point, low‑vapor liquids.

💭 Think About

• First, recall whether a grade E combustible liquid is associated with relatively low or relatively high flash points compared to gasoline or kerosene. • Look at each option and ask: does this describe a highly volatile fuel like gasoline, or a heavy, relatively hard‑to‑ignite product like Bunker C? • Think about whether Bunker C is likely to give off large amounts of vapor at normal ambient temperatures, or mostly when it is heated significantly.

✅ Before You Answer

• Verify the definition of flash point ranges that correspond to grades A through E in USCG/46 CFR references (especially the minimum flash point for grade E). • Check whether Reid vapor pressure of 14 psi or more is typical of very volatile products (like gasoline) or of heavy fuel oils. • Confirm that self‑ignition (auto‑ignition) temperature is normally far higher than the flash point and see whether “below 150°F (65.5°C)” is realistic for a heavy fuel like Bunker C.