( ( ( ( A pH ) ( of 7 ) ) ( -LRB- ( ( pure water ) -RRB- ) ) ) ( ( means ( ( a concentration ) ( of ( ( ( 10 -7 ) or ) ( one tenmillionth ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NP (DT A) (NN pH)) (PP (IN of) (NP (CD 7)))) (PRN (-LRB- -LRB-) (NP (JJ pure) (NN water)) (-RRB- -RRB-))) (VP (VBZ means) (NP (NP (DT a) (NN concentration)) (PP (IN of) (NP (NP (CD 10) (CD -7)) (CC or) (NP (CD one) (NN tenmillionth)))))) (. .)))
A pH of 7 (pure water) means a concentration of 10 -7 or one tenmillionth.
(ROOT (S (NP (CD 7)) (VP (VBZ is) (NP (NP (DT the) (NN ph)) (PP (IN of) (NP (JJ pure) (NN water))))) (. .)))