🔍 Key Concepts

• Difference between elemental gases (like nitrogen, oxygen) and chemical classifications based on carbon and hydrogen • Meaning of hydrocarbon (compounds of only carbon and hydrogen) • How adding other atoms (like chlorine, fluorine, oxygen) changes the type of chemical compound

💭 Think About

• Look at which options mention only carbon and hydrogen versus carbon, hydrogen, and other atoms. Which of these sounds like a special class of organic chemicals? • Consider whether a “chemical gas” in hazardous materials contexts is limited to hydrocarbons only, or can include compounds with other elements. • Which option sounds too restrictive to cover the many different industrial gases carried by ships (e.g., chlorine, ammonia, etc.)?

✅ Before You Answer

• Identify which choice best fits common hazardous gases carried on tankers (think: do they all contain only carbon and hydrogen?). • Check which answer describes a broad enough definition to include inorganic gases (like chlorine) and organic gases (like propane). • Eliminate any option that is really just defining hydrocarbons, not all chemical gases.