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lanh145632
2 năm trước
Trong tự nhiên brom có hai đồng vị bền : chiếm 50,69% số nguyên tử và chiếm 49,31% số nguyên tử. a/ Hãy tìm nguyên tử khối trung bình của brom.b/ Tính số nguyên tử khi có 50 nguyên tử hoặc 1500 nguyên tử hai loại đồng vị ? c/ Tính % theo khối lượng trong HBrO4
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