( ( If ( ( a gas ) ( is ( ( ( driven out ) ( of ( the flask ) ) ) ( during ( the reaction ) ) ) ) ) ) ( , ( ( the system ) ( ( does ( work ( on ( its surroundings ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (IN If) (S (NP (DT a) (NN gas)) (VP (VBZ is) (VP (VBN driven) (PRT (RP out)) (PP (IN of) (NP (DT the) (NN flask))) (PP (IN during) (NP (DT the) (NN reaction))))))) (, ,) (NP (DT the) (NN system)) (VP (VBZ does) (NP (NP (NN work)) (PP (IN on) (NP (PRP$ its) (NNS surroundings))))) (. .)))
If a gas is driven out of the flask during the reaction, the system does work on its surroundings.
(ROOT (S (NP (DT A) (JJ sealed) (, ,) (JJ vacuum-insulated) (NN reaction) (NN flask)) (VP (VBZ approximates) (NP (NP (DT the) (NN condition)) (PP (IN of) (NP (NP (DT a) (VBN isolated) (NN system)) (, ,) (SBAR (WHPP (IN in) (WHNP (WDT which))) (S (NP (CC neither) (NP (NN matter)) (CC nor) (NP (NN heat))) (VP (MD can) (VP (VB be) (VP (VBN exchanged) (PP (IN between) (NP (NN system) (CC and) (NNS surroundings)))))))))))) (. .)))
A sealed, vacuum-insulated reaction flask approximates the condition of a isolated system, in which neither matter nor heat can be exchanged between system and surroundings.