As we see in Section 1.6, the carbon atom can form four covalent bonds to other atoms — especially other carbon atoms. 为什么碳原子在生命化学中扮演着如此重要的角色,它又有什么特别之处呢?首先,当碳是主要组成结构时,可能的化合物是极其多样化的。正如我们在接下来的第1.6节中看到的一样,碳原子可以...
Why does sand conduct heat better than water? What is the pH of a 0.250 M solution of methylamine ( CH_3NH_2, K_b=4.4 \times 10^{-4} )? If a carbon atom has four valence electrons, which of the following statements are true...
Which of the following does not contribute to the non-covalent interactions that stabilize the helical strands of DNA? a. hydrophobic interactions b. phosphodiester bonds c. hydrogen bonds d. base stacking e. none of the above Could water...
4. Valency of Carbon: Carbon has four valencies, which means it can form four covalent bonds. In alkanes, all four valencies of each carbon atom are satisfied by bonding with hydrogen atoms or other carbon atoms. 5. Absence of D-Orbitals: Carbon does not have vacant d-orbitals that co...
男，62岁。急性重症胰腺炎病人在保守治疗中，尿量逐渐减少，无尿2日，出现气促，全身水肿，血压180／92mmHg。心率120次／分，听诊闻及两下肺布满细湿啰音，查血钾6.9mmol／L，血尿素氮25mmol／L，肌酐577μmol／L。目前应采取的最有效治疗手段是
In valence bond theory, \boxed{\space} is the mixing of atomic orbitals to generate new sets of orbitals that are then available to form covalent bonds with other atoms a. pi mixing b. antibonding c. sigma mixing d. hybridization Describe the...
Covalent bonds with large dipoles (i.e. large differences in electronegativity) are worth looking paying attention to: frequently, this will be where the “action” is. “Hold on”, you might say. “I thought electron densities were reflected by their charges, like in H3O+, BF4–, and ...
• having strong hydrogen bonds that gives it a strong surface tension (three times that of liquid ammonia) – which would encourage the aggregation of prebiotic compounds and the development of membranes; • being able to form weak non-covalent bonds with other compounds – which, for exampl...
Why does an electron cloud want to have a stable amount of electrons per energy level? Why is there much less subduction around the Atlantic than the Pacific ? Why do we use prefixes only in covalent compounds? With reference to covalent and ionic bonds. why does...
bonds will be there. In the Lewis Structure of an AlCl3 molecule, how many nonbonding electrons are around the central atom? What is the Lewis structure of the covalent compound that contains one nitrogen atom, one hydrogen atom, and one carbon atom?