1.解,设生成71g五氧化二磷需要氧气X克,红磷y克: 4 P + 5 O2 =点燃= 2 P2 O5 124 160 284 y g x g 71g 124/284=yg/71g Y=124*71g/284 y=8804g/284=31g 160/254=xg/71g X=160*71g/284 x=11360g/284=40g 答:生成71g五氧化二磷需要氧气40g.红磷31g. 2.解,设生成71g五氧化二磷需要氧气X克,红磷y克: 4 P + 5 O2 =点燃= 2 P2 O5 124 160 284 y g x g 71g 124/yg=284/71g Y=124*71g/284 y=8804g/284=31g 160/xg=284/71g x=124*71g/284 x=11360g/284=40g 答:生成71g五氧化二磷需要氧气40g.红磷31g.