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thinphuoc
2 năm trước
B là hợp chất của nguyên tố y với H. Tỉ lệ số nguyên tử trong phân tử B là 1:3, trong đó y chiếm 82,35 % về khối lượng. a) Tính nguyên tử khối của y, xác định tên, kí hiệu hoá học của y. b) Tính phân tử khối của B, nếu phân tử chỉ có nguyên tử y. c) Phân tử B nặng hơn hay nhẹ hơn phân tử H bao nhiêu lần
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