Master TEAS 7 Science 2026 — Unleash Your Inner Scientist in Style!

A compound gas is made from more than one element chemically bound together in a fixed ratio. Ammonia fits this because its formula NH3 shows nitrogen combined with hydrogen in a 1:3 ratio, forming a single molecule made of two different elements. The other gases are elemental in nature: oxygen as O2, nitrogen as N2, and hydrogen as H2, each consisting of only one element. So they are not compounds. Ammonia is the compound gas.