For gases measured at the same temperature and pressure, reacting volume ratios are given by what?

1. Equal volumes of ideal gases at matched temperature and pressure hold equal numbers of molecules. 2. A balanced equation counts molecules, so those same numbers apply directly to volumes. 3. The reacting volume ratios are therefore just the balancing coefficients. 4. For nitrogen plus three hydrogen giving two ammonia, one volume of nitrogen takes three volumes of hydrogen and yields two volumes of ammonia. 5. This shortcut only works while every volume is measured at the same temperature and pressure. _Source: OpenStax Chemistry (CC BY 4.0), Ch 9 "Gases", section 9.3 Stoichiometry of Gaseous Substances, Mixtures, and Reactions_