( ( ( A combination ) ( of ( ( ( two or ) more ) chemicals ) ) ) ( ( not ( involving ( a ( chemical reaction ) ) ) ) . ) )
(ROOT (S (NP (NP (DT A) (NN combination)) (PP (IN of) (NP (QP (CD two) (CC or) (JJR more)) (NNS chemicals)))) (VP (RB not) (S (VP (VBG involving) (NP (DT a) (JJ chemical) (NN reaction))))) (. .)))
A combination of two or more chemicals not involving a chemical reaction.
(ROOT (S (NP (DT A) (NN combination) (NN reaction)) (VP (VBZ is) (NP (NP (DT a) (NN reaction)) (SBAR (WHPP (IN in) (WHNP (WDT which))) (S (NP (CD two) (CC or) (JJR more) (NNS substances)) (VP (VBP combine) (S (VP (TO to) (VP (VB form) (NP (DT a) (JJ single) (JJ new) (NN substance)))))))))) (. .)))