関連ワード:  is gas a mixture compound or element    is gasoline a mixture compound or element    is oxygen gas a mixture compound or element    is hydrogen gas a mixture compound or element    is neon gas a mixture compound or element    is chlorine gas a mixture compound or element    is nitrogen gas a mixture compound or element    is ammonia gas a mixture compound or element    is gasoline a element compound mixture or none    is helium gas a compound element or mixture