Câu 1: a/Viết công thức tỉ khối của khí A so với khí A, tỉ khối của khí A so với không khí. b/ Cho các khí CH4, O2, CO2, N2O, H2. Khí nào nhẹ hơn không khí. Câu 2: a/ Hệ thống tính chất hóa học của H2 (có PTHH minh họa cho mỗi tính chất, và điều kiện xảy ra phản ứng). b/ Trình bày cách điều chế khí Hidro trong phòng thí nghiệm: - Hóa chất - PTHH - Cách thu khí Câu 3: Cho m gam kẽm tác dụng đủ với dung dịch chứa a gam axit clohidirc (HCl), sau phản ứng thu được 6,72 lít khí H2 (đktc). Tính m, a?

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