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dangkhiem2000
2 năm trước
Cho em hỏi là + tại sao lại thêm 2 vào trước H2 để cân bằng phương trình H2 + O2 - - ->H2O ? + làm thế nào để 4Na + O2 = 2Na2O ?? kiểu như rút gọn hay như thế nào ạ
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