Modifiers matching reactant:

• simple,
• single,
• off,
• liquid,
• gaseous,
• stable,
• volatile,
• inexpensive,
• organic,
• small,
• hazardous,
• polar,
• dissolved,
• immune,
• nonvolatile,
• poisonous,
• mobile,
• strong,
• dangerous,
• chemical,
• cationic,
• biochemical,
• harmful,
• essential,
• inflammatory,
• residual,
• endogenous,
• cementitious,

Simple categories matching gaseous:

• olefin,
• fuel,
• chemical,
• form,
• hydrocarbon,
• alkyne,
• reactant,
• compound,
• odor,
• plasma,
• fluid,
• molecule,
• mixture,
• matter,
• substance,
• alkane,
• waste,
• mass,
• cyanide,
• object,
• contaminant,
• phenomenon,
• medium,
• component,
• state,
• anesthetic,
• fumigant,
• atmosphere,
• system,
• monomer,
• contamination,
• material,
• precursor,
• sulphide,
• pollutant,
• substrate,
• salt,
• carrier,
• agent,
• acid,
• constituent,
• anaesthetic,
• body,
• oxide,
• buffer,
• impurity,
• flow,