Which gas is commonly referred to with a specific gravity of -66?

The gas that is commonly associated with a specific gravity of -66 is natural gas. Specific gravity is a measure of the density of a substance compared to the density of air. In the case of natural gas, it is primarily composed of methane, which has a specific gravity of about 0.6. When we refer to specific gravities, it's important to note that many gases, including natural gas, are lighter than air. Therefore, when we talk about a specific gravity that can be interpreted as being "negative" in a colloquial sense, it signifies that the gas is significantly lighter than air, leading to it being buoyant.

Natural gas is widely utilized in heating, cooking, and as a fuel for vehicles due to its efficiency and cleanliness compared to other fossil fuels. Methane, while a key component of natural gas, does not specifically relate to a specific gravity of -66; instead, it's the mix and characteristics of the entire gaseous product that provides that measurement.

Understanding the specific gravity of natural gas highlights its behavior in the environment, particularly its tendency to rise in the air when released, making it important for safety measures in plumbing and gas installation.