( ( This law ) ( ( says ( that ( ( when ( ( a ( chemical reaction ) ) ( ( rearranges atoms ) ( into ( a ( new product ) ) ) ) ) ) ( , ( ( ( the mass ) ( of ( ( the reactants ) ( -LRB- ( ( chemicals ( before ( the ( chemical reaction ) ) ) ) -RRB- ) ) ) ) ) ( is ( ( the same ) ( as ( ( ( the mass ) ( of ( the products ) ) ) ( -LRB- ( ( ( the ( new chemicals ) ) made ) -RRB- ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT This) (NN law)) (VP (VBZ says) (SBAR (IN that) (S (SBAR (WHADVP (WRB when)) (S (NP (DT a) (NN chemical) (NN reaction)) (VP (VBZ rearranges) (NP (NNS atoms)) (PP (IN into) (NP (DT a) (JJ new) (NN product)))))) (, ,) (NP (NP (DT the) (NN mass)) (PP (IN of) (NP (NP (DT the) (NNS reactants)) (PRN (-LRB- -LRB-) (NP (NP (NNS chemicals)) (PP (IN before) (NP (DT the) (NN chemical) (NN reaction)))) (-RRB- -RRB-))))) (VP (VBZ is) (NP (NP (DT the) (JJ same)) (PP (IN as) (NP (NP (DT the) (NN mass)) (PP (IN of) (NP (DT the) (NNS products))) (PRN (-LRB- -LRB-) (NP (NP (DT the) (JJ new) (NNS chemicals)) (VP (VBN made))) (-RRB- -RRB-))))))))) (. .)))
This law says that when a chemical reaction rearranges atoms into a new product, the mass of the reactants (chemicals before the chemical reaction) is the same as the mass of the products (the new chemicals made).
(ROOT (S (NP (NNS Atoms)) (VP (VBP make) (NP (NNS products)) (PP (IN by) (S (VP (VBG rearranging) (NP (PRP$ their) (NN chemical) (NNS bonds)) (PP (IN in) (NP (DT a) (NN reactant))))))) (. .)))