1. Hòa tan hoàn toàn hỗn hợp Z gồm Cu và CuO trong dung dịch HNO3 loãng dư thu được 0,896 lít NO (đkc) là sản phẩm khử duy nhất và dung dịch chứa 37,6 gam Cu(NO3)2. Tính % khối lượng của Cu trong Z. 2. Hòa tan hoàn toàn 14,08 gam hỗn hợp X gồm Cu và CuO bằng dung dịch HNO3 30% (lấy dư) thu được dung dịch Y và thoát ra 1,792 lít khí NO (đktc, là sản phẩm khử duy nhất). Biết lượng HNO3 dùng dư 20% so với lượng vừa đủ, tính khối lượng CuO và m dd HNO3

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