Is propane heavier or lighter than air?

Propane is heavier than air, which is why the correct answer is that it is classified as heavier. Understanding this property is important for safety reasons, particularly in scenarios where propane is used, such as heating, cooking, or as a fuel in various appliances.

When propane gas leaks, it tends to accumulate in low areas and enclosed spaces rather than dissipating into the atmosphere as lighter gases would. This characteristic can pose a hazard because it may lead to potential build-up and increase the risk of explosion or fire if an ignition source is present. Consequently, proper ventilation and monitoring are essential in areas where propane is stored or utilized to mitigate such risks.

The other options do not apply because propane does not exhibit properties of being equal to air or variable depending on temperature in the context of its density relative to air. Its specific gravity is consistently greater than 1.0, indicating its heaviness compared to air regardless of temperature variations.