Preparatory Problems for the 44th International Chemistry Olympiad  (Bấm vào liên kết phía dưới để tải xuống)

We are happy to provide Preparatory Problems for the 44th International Chemistry Olympiad. These problems were prepared with reliance on fundamental topics that are traditionally covered in high school chemistry courses supplemented with six topics of advanced difficulty for the Theoretical part and one topic of advanced difficulty for the Practical part.

Theoretical Problems Problem 1. Structures of Boron Hydrides and NMR Spectroscopy The study of boranes (boron hydrides) has played an especially important role in understanding broad structural principles. Work in this area began in 1912 with the classic research of Alfred Stock (1876–1946), and chemists soon learned that the boranes had unusual stoichiometries and structures and an extensive and versatile reaction chemistry. William Lipscomb (1919–2011) received the Nobel Prize in 1976 “for his studies of boranes which … illuminated problems in chemical bonding.” a) Predict the most likely structure for the BH4 – ion. The BH4 – ion is tetrahedral. That is, the H atoms of the borohydride ion are tetrahedrally arranged and are equivalent. b) The 1H NMR spectrum of the BH4 – ion is illustrated below. It consists of a 1:1:1:1 multiplet along with a smaller 7-line multiplet. (The nuclear spin for 1H is ½, for 11B it is 3/2 and for 10B it is 3.) Interpret this spectrum.

Tải xuống để xem tài liệu hoàn chỉnh - Chia sẻ cho bạn bè nếu trang web có ích với bạn!
Nguồn tài liệu:

Bạn cũng có thể quan tâm:

Bài tập môn Hóa Học lớp Lớp 10
Mời bạn tham gia hỏi - đáp
Thư viện bài tập © 2014 -2017 - Liên hệ - Giới thiệu - Bản quyền - Chính sách bảo mật - Sitemap