1 Dãy chất nào sau đây gồm các hợp chất? A. NaCl, NH 3 , SO 2 . B. CaCO 3 , N 2 , Cu. C. O 2 , C, Al. D. C, P, Fe. 2 Cách viết 2 O có ý chỉ là: A. 2 nguyên tố Oxi. B. 1 phân tử Oxi. C. 2 nguyên tử Oxi. D. 2 phân tử Oxi. Câu 6: Công thức hóa học của axit nitric, biết trong phân tử gồm 1H, 1N, 3O là: A. HNO 3 . B. HNO. C. H 3 NO. D. HN 3 O. Câu 7: Cho Ba(II), (SO 4 )(II). Hãy chọn công thức hóa học đúng nhất: A. Ba 2 SO 4 . B. Ba(SO 4 ) 2 . C. Ba 2 (SO 4 ) 2 . D. BaSO 4 . Câu 8: Hóa trị của nguyên tố N trong hợp chất N 2 O, NO, NO 2 , N 2 O 5 lần lượt là: A. V, IV, II, I. B. V, II, IV, I. C. I, II, V, IV. D. I, II, IV, V.

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