Có bốn kim loại Na, Al, Fe, Cu. Thứ tự tính khử giảm dần là

A.Al, Na, Cu, Fe

B. Na, Fe, Cu, Al

C. Na, Al, Fe, Cu

D. Cu, Na, Al, Fe.

Dãy gồm các kim loại đều phản ứng với nước ở nhiệt độ thường là:

A. Na, Fe, K

B. Na, Cr, K

C. Be, Na, Ca

D. Na, Ba, K

Cho các kim loại sau: Al, Zn, Fe, Cu, Cr, Ag. Số kim loại có thể tan được trong dung dịch kiềm ở điều kiện thích hợp là

A. 1                             

B. 2                             

C. 3                             

D. 4

Hợp chất nào dưới đây không thể tham gia phản ứng trùng hợp?

A. Axit ɛ-aminocaproic.

B. Caprolactam.

C. Buta-1,3-đien.

D. Metyl metacrylat.

Thủy tinh hữu cơ plexiglas là loại chất dẻo rất bền, trong suốt, có khả cho gần 90% ánh sáng truyền qua nên được sử dụng làm kính ô tô, máy bay, kính xây dựng, kính bảo hiểm,.... Polime dùng để chế tạo thủy tinh hữu cơ có tên gọi là:

A. Poli (metyl metacrylat)

B. poli acrilonitrin.

C. poli (etylen terephtalat).

D. poli (hexametylen ađipamit).

lan want make sandwiches but she have not bread

My favorite movie is "A Walk To Remember". This is my favorite movie because it deals with real life issues, like some of the most important things in life such as: love, relationships, and most important, who your real friends are. "A Walk To Remember is about a girl named Jamie (Mandy Moore) who is the daughter of a minister who becomes ill. During high school Jamie doesn't have very many friends but is in alot of activities and through that she meets a reckless boy named Landon. Landon got into some trouble which made the principal force him into being in a play for the drama club. Landon Played a lead role as did Jamie, even though they didn't hang out in the same crowd of friends when Landon needed Giúp with his lines in the play he turned to Jamie to Giúp him out. One of the first things she told Landon was for him to promise that he wouldn't fall in love with her. But that is a promise that he did not keep. Jamie finally told Landon that she had cancer and the treatment stoped working so she didn't have very much time to live. Jamie had this list of accomplisments that she wanted to make before she passed. The number one thing was to get married at the same church that her mother and father was married in. Landon made ALL of her dreams come true. But unfortunitally her cancer became worse and she died. I would recommend this movie to anyone who likes heart touching stories, I liked it and would watch it a million times a day if I could.

Khi phản ứng với dung dịch HCl, crom tạo thành sản phẩm muối có công thức hóa học là

A. CrCl₆.

B. CrCl₄.

C. CrCl₃.

D. CrCl₂

Cho CH₃CHO phản ứng với H₂ (xúc tác Ni, đun nóng) thu được

A. CH₃OH.

B. CH₃CH₂OH.

C. CH₃COOH.

D. HCOOH.