( ( The ( molecular weight ) ) ( ( is ( equal ( to ( ( the sum ) ( of ( ( the ( relative ( atomic masses ) ) ) ( of ( all ( the ( atoms ( that ( comprise ( the molecule ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (JJ molecular) (NN weight)) (VP (VBZ is) (ADJP (JJ equal) (PP (TO to) (NP (NP (DT the) (NN sum)) (PP (IN of) (NP (NP (DT the) (JJ relative) (JJ atomic) (NNS masses)) (PP (IN of) (NP (PDT all) (DT the) (NNS atoms) (SBAR (WHNP (WDT that)) (S (VP (VBP comprise) (NP (DT the) (NN molecule))))))))))))) (. .)))
The molecular weight is equal to the sum of the relative atomic masses of all the atoms that comprise the molecule.
(ROOT (S (NP (NP (DT The) (NN sum)) (PP (IN of) (NP (NP (DT the) (NNS masses)) (PP (IN of) (NP (NP (DT the) (NNS atoms)) (PP (IN in) (NP (DT the) (NN formula)))))))) (VP (VBZ is) (VP (VBN referred) (PP (TO to) (NP (RB as) (JJ molecular) (NN mass))))) (. .)))