Question

In: Chemistry

2. Ortho-dichlorobenzene has a molecular weight of 147.00 g/mol, but its MS has a very small...

2. Ortho-dichlorobenzene has a molecular weight of 147.00 g/mol, but its MS has a very small relative abundance of the 147 peak. Instead, it has peaks at 146 (100% relative abundance), 148 (65%), and 150 (10.6%). The peak at 147 is about 6.6% as big as the 146 peak. What causes this distinctive molecular ion region for this compound? What peaks (note the plural) would you expect to see on the mass spectrum for the fragment (note the lack of plural) caused by loss of one chlorine atom (one of the C-Cl bonds breaking) during the ionization process?

Solutions

Expert Solution

Ortho dichloro benzene molecular weight is 147 g/mole. It is calculated as follows

C6H4Cl2 for Carbon Molecular weight of Carbon is 12 so                          12X6 = 72

          For Hydrogen Molecular weight of Hydrogen is 1 so                            1X4 = 04

For Chlorine average Molecular weight of Chlorine is 35.453 i.e so      35.5X2 = 71

                                                                                                                        Total =147

However in nature chlorine is available in two isotopic forms they are 35Cl and 37Cl with relative abundance of 75.8% and 24.2% respectively. So we get molecular ion peak for 35Cl at m/z value 146 and M+H+ at m/z value 147 and we get molecular ion peak for 37Cl at m/z value 148 and M+H+ at m/z value 149 and combination of both isotopes at m/z value 150. During the fragmentation process after elimination of one chlorine atom we get molecular ion peak for 35Cl at m/z value 111 and M+H+ at m/z value 112 and we get molecular ion peak for 37Cl at m/z value 113 and M+H+ at m/z value 114 and combination of both isotopes at m/z value 115.                                                                                             


Related Solutions

Acetic acid (molecular weight = 60.05 g/mol) and sodium acetate (molecular weight = 82.03 g/mol) can...
Acetic acid (molecular weight = 60.05 g/mol) and sodium acetate (molecular weight = 82.03 g/mol) can form a buffer with an acidic pH. In a 500.0 mL volumetric flask, the following components were added together and mixed well, and then diluted to the 500.0 mL mark: 100.0 mL of 0.300 M acetic acid, 1.00 g of sodium acetate, and 0.16 g of solid NaOH (molecular weight = 40.00 g/mol). What is the final pH? The Ka value for acetic acid...
Luminol has a molecular weight of 177 g/mol. The forensic technician at a crime scene has...
Luminol has a molecular weight of 177 g/mol. The forensic technician at a crime scene has just prepared a luminol stock solution by adding 14.0 g of luminol into a total volume of 75.0 mL of H2O. Before investigating the scene, the technician must dilute the luminol solution to a concentration of 6.00×10−2 M . The diluted solution is then placed in a spray bottle for application on the desired surfaces. What volume of the stock solution (Part A) would...
1. a. A nylon 6,6 has an average molecular weight of 12078 g/mol. Calculate the average...
1. a. A nylon 6,6 has an average molecular weight of 12078 g/mol. Calculate the average degree of polymerization to 1 decimal of accuracy assuming the Nylon 6-6 mer is C12H22O2N2. b. Write a general chemical reaction for the chain polymerization of ethylene monomer into the linear polymer polyethylene. c. In general how does the processing of thermoplastics into the desired shape differ from the processing of thermosetting plastics? d. How can the higher strength of polyvinyl chloride as compared...
The molecular weight of methylene blue is 320 g/mol. The concentration of the original sample was...
The molecular weight of methylene blue is 320 g/mol. The concentration of the original sample was 0.005 mg/ml in 10 ml. Determine the molarity (M) of your original sample and each dilution. Original: Dilution 1 (1:2 add 3mL of methylene blue + 3mL of water) : Dilution 2 (1:4 use 3mL of of 1:2 solution + 3mL of water) : Dilution 3 (1:8 use 3mL of 1:4 solution + 3 mL of water) : Dilution 4 (1:10 use 0.5 ml...
Cytochrome C has a relative molecular weight of 11,384 g/mol. Calculate the extinction coefficient of cytochrome...
Cytochrome C has a relative molecular weight of 11,384 g/mol. Calculate the extinction coefficient of cytochrome C at 405nm from 6.1 mg/mL. Absorbance = 3.045
Phenylephrine HCL has a molecular weight of 203.66 g/mol. How many formula units are in 10...
Phenylephrine HCL has a molecular weight of 203.66 g/mol. How many formula units are in 10 mg of phenylephrine HCL?
A molecule with molecular weight of 180.18 g/mol is analyzed and found to contain 40.00% carbon,...
A molecule with molecular weight of 180.18 g/mol is analyzed and found to contain 40.00% carbon, 6.72% hydrogen and 53.28% oxygen. What is the empirical and molecular formulas of the molecule? (C=12.01 g/mol, H=1.01 g/mol, and O= 16.00 g/mol) I know the answer, but please explain how you get to it.....
The average molecular weight of the triglycerides in coconut oil is 680 g/mol. How much NaOH...
The average molecular weight of the triglycerides in coconut oil is 680 g/mol. How much NaOH (in grams) is required to completely saponify this oil? Why is it important to use less than this amount when preparing soap?
1-What is a mol of a species of molecular weight , in terms of (a) a...
1-What is a mol of a species of molecular weight , in terms of (a) a number of molecules? (b) a mass? 2-What is a ton-mole of a species? 3-How many lb-moles and lb of (a) H and (b) H are contained in 1 lb-mole of H O? 4-How many gram-moles of C H are contained in 2 kmol of this substance? 5-One hundred kilograms of molecular hydrogen (H ) is fed into a reactor each hour. What is the...
The density of sodium is 0.971 g/cm3 and it has an atomic weight of 22.9897 g/mol....
The density of sodium is 0.971 g/cm3 and it has an atomic weight of 22.9897 g/mol. Each sodium atom contributes one valence electron to the metal, so the number of electrons per unit volume, N/V, is equal to the number of sodium atoms per unit volume.    a) Calculate the number density of atoms per unit volume, N/V.    b) Calculate the Fermi energy of sodium.    c) Calculate the Fermi temperature.   d) At room temperature (298 K), calculate the chemical potential.  ...
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT