设消耗O2的质量是x
4 NH3 + 3 O2 ==点燃== 2 N2 + 6 H2O
4*17 3*32
340 g x
(4*17)/(3*32) = 340 g / x
解得x = 480 g
即340 g氨气完全燃烧消耗氧气480 g