( ( Compare ( ( the ( two sets ) ) ( of ( ( mole ratios ) ( -LRB- ( ( ( ( ( 1 - ) ( those ( of ( ( ( the ( balanced equation ) ) , ) 2 ) ) ) ) - ) ( those ( determined ( from ( the ( given masses ) ) ) ) ) ) -RRB- ) ) ) ) ) ) . )
(ROOT (S (VP (VB Compare) (NP (NP (DT the) (CD two) (NNS sets)) (PP (IN of) (NP (NP (JJ mole) (NNS ratios)) (PRN (-LRB- -LRB-) (NP (NP (CD 1)) (: -) (NP (NP (DT those)) (PP (IN of) (NP (NP (DT the) (JJ balanced) (NN equation)) (, ,) (NP (CD 2)))))) (: -) (S (NP (DT those)) (VP (VBD determined) (PP (IN from) (NP (DT the) (VBN given) (NNS masses))))) (-RRB- -RRB-)))))) (. .)))
Compare the two sets of mole ratios (1- those of the balanced equation, 2- those determined from the given masses).
(ROOT (S (NP (DT A) (NN student)) (VP (MD should) (VP (VB use) (NP (DT a) (NN balance) (S (VP (TO to) (VP (VB compare) (NP (NP (DT the) (NNS masses)) (PP (IN of) (NP (CD two) (JJ small) (NNS rocks)))))))))) (. .)))