When an electron absorbs energy, it will move up from a lower energy level to a higher energy level, called the "excited state" of the negatively-charged subatomic particle.<span> However, the absorbed energy is released within a small interval of time and the electron moves down to its "ground state."</span>
Answer:
Four possible isomers (1–4) for the natural product essramycin. The structure of compound 1 was attributed to essramycin by 1H NMR, 13C NMR, HMBC, HRMS, and IR experiments.
Explanation:
Three synthetic routes were used to prepare all four compounds (Figure 2A). All three reactions utilize 2-(5-amino-4H-1,2,4-triazol-3-yl)-1-phenylethanone (5) as the precursor, whereas each uses different esters (6–8) to construct the pyrimidinone ring. Isomer 1 was prepared by reaction A, which used triazole 5 and ethyl acetoacetate (6) in acetic acid. This was the reaction used in syntheses of essramycin by the Cooper and Moody laboratories.3,4 Reaction B produced compound 2 (minor product) and compound 3 (major product), which were separated chromatographically. This reaction allowed reagent 5 to react with ethyl 3-ethoxy-2-butenoate (7) in the presence of sodium in methanol, under reflux for 24 h. Compound 4 was prepared by reaction C, which was obtained by reflux of 5 and methyl 2-butynoate (8) in n-butanol.
Answer:
157.8 g
Explanation:
Step 1: Write the balanced equation
Fe₂O₃ + 3 CO ⟶ 3 CO₂ + 2 Fe
Step 2: Calculate the moles corresponding to 209.7 g of Fe
The molar mass of Fe is 55.85 g/mol
209.7 g × 1 mol/55.85 g = 3.755 mol
Step 3: Calculate the moles of CO needed to produce 3.755 moles of Fe
The molar ratio of CO to Fe is 3:2. The moles of CO needed are 3/2 × 3.755 = 5.633 mol
Step 4: Calculate the mass corresponding to 5.633 moles of CO
The molar mass of CO is 28.01 g/mol.
5.633 mol × 28.01 g/mol = 157.8 g
I would say b is the correct answer