câu 1: cho 18,6 gam hỗn hợp gồm Kẽm và Sắt tác dụng với dung dịch axit sunfuric loãng dư, khi phản ứng kết thúc thu được 6,72 lít khí H2 (đktc). Xác định % của các kim loại trong hỗn hợp ban đầu. Tính khối lượng muối thu được khi kết thúc phản ứng câu 2: cho 20gam hỗn hợp bột Mg và Fe tác dụng hết với dung dịch HCl thấy có 1 gam khí H2 thoát ra. Xác định % của các kim loại trong hỗn hợp ban đầu. Tính khối lượng muối thu được khi kết thú phản ứng

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