関連ワード:  is o2 a flammable gas    is oxygen a flammable gas    is oxygen a flammable gas by itself    is oxygen a flammable gases    oxygen is a flammable gas true or.false    is oxygen a non flammable gas    is oxygen a highly flammable gas    is compressed oxygen a flammable gas    is medical oxygen a flammable gas    is pure oxygen a flammable gas