🔍 Key Concepts

• Lower and Upper Flammable Limits (LFL/UFL) of vapors in air and what the percentage range represents • How to read entries in the Chemical Data Guide for Bulk Shipment by Water (look for “Flammable limits in air (%)”) • Typical flammable range behavior of highly reactive, explosive gases like ethylene oxide

💭 Think About

• First, think about whether ethylene oxide behaves more like a normal hydrocarbon (narrow range) or like a very reactive gas (potentially wide flammable range). Which choice reflects that? • Look at the lower number in each choice: does the LFL for a very easily ignited gas tend to be higher than 3%, or can it be lower than 3%? Eliminate ranges that don’t make sense. • Compare the upper limits given: for an extremely reactive gas, would you expect an upper limit closer to 30–50%, or can it extend much higher toward 100%? Use that to narrow the options.

✅ Before You Answer

• In the actual Chemical Data Guide, locate the specific line labeled “Flammable limits in air (%)” for ethylene oxide and confirm both the lower and upper values. • Verify you’re not confusing flash point or autoignition temperature with flammable limits—these are different properties. • Check that the selected range looks realistic compared to other common chemicals you know; an extremely broad range is characteristic of some highly reactive materials.