( ( ( The ( percent yield ) ) ( of ( a ( reaction product ) ) ) ) . )
(ROOT (NP (NP (DT The) (NN percent) (NN yield)) (PP (IN of) (NP (DT a) (NN reaction) (NN product))) (. .)))
The percent yield of a reaction product.
(ROOT (S (NP (NP (DT The) (NN amount)) (PP (IN of) (NP (NP (NN product)) (SBAR (WHNP (WDT that)) (S (VP (MD may) (VP (VB be) (VP (VBN produced) (PP (IN by) (NP (DT a) (NN reaction))) (PP (IN under) (NP (VBN specified) (NNS conditions))))))))))) (VP (VBZ is) (VP (VBN called) (NP (JJ theoretical) (NN yield)))) (. .)))
The amount of product that may be produced by a reaction under specified conditions is called theoretical yield.