Question

The formula of nitrobenzene is C6H5NO2. The molecular weight of this compound is ________ amu.

A. 109.10
B. 3.06
C. 107.11
D. 123.11
E. 43.03

Answer 1

The molecular weight of nitrobenzene is D) 123.11 amu.

Step-by-step explanation:

The molecular weight of nitrobenzene can be determined by adding up the atomic weights of its constituent elements. The formula C6H5NO2 consists of 6 carbon atoms, 5 hydrogen atoms, 1 nitrogen atom, and 2 oxygen atoms. The atomic weights of carbon, hydrogen, nitrogen, and oxygen are approximately 12.01 amu, 1.01 amu, 14.01 amu, and 16.00 amu, respectively. Therefore, the molecular weight of nitrobenzene is calculated as follows:

1. 6 carbon atoms * 12.01 amu/carbon atom = 72.06 amu
2. 5 hydrogen atoms * 1.01 amu/hydrogen atom = 5.05 amu
3. 1 nitrogen atom * 14.01 amu/nitrogen atom = 14.01 amu
4. 2 oxygen atoms * 16.00 amu/oxygen atom = 32.00 amu
5. Total molecular weight = 72.06 amu + 5.05 amu + 14.01 amu + 32.00 amu = 123.12 amu

Therefore, the correct answer is D. 123.11 amu.