# Cacodylic Acid [(CH3)2AsOOH] Molecular Weight Calculation

The molecular weight of Cacodylic acid [(CH3)2AsOOH] is 137.997795. Cacodylic acid [(CH3)2AsOOH] is an organic compound of four elements: Carbon (C), Hydrogen (H), Arsenic (As), and Oxygen (O). The molecular weight of Cacodylic acid is 137.997795 which can be calculated by adding up the total weight (atomic weight multiplied by their number) of  Carbon, Hydrogen, Arsenic, and Oxygen.

# CALCULATION PROCEDURE: Cacodylic acid [(CH3)2AsOOH] Molecular Weight Calculation

Step 1: Find out the chemical formula and determine constituent atoms and their number in a Cacodylic acid molecule.
You will know different atoms and their number in a Cacodylic acid molecule from the chemical formula. The chemical formula of Cacodylic acid is [(CH3)2AsOOH] or [C2H7AsO2]. From the chemical formula, you can find that one molecule of Cacodylic acid has two Carbon (C) atoms, seven Hydrogen (H) atoms, one Arsenic (As) atom, and two Oxygen (O) atoms.

Step 2: Find out the atomic weights of each atom (from the periodic table).

Atomic weight of Carbon (C): 12.0107 (Ref: Jlab-ele006)
Atomic weight of
Hydrogen (H): 1.008 (Ref: Lanl-1)
Atomic weight of Arsenic (As): 74.921595 (Ref: Jlab-ele033, ciaaw-arsenic)
Atomic weight of Oxygen (O): 15.9994 (Ref: Jlab-ele008)

Step 3: Calculate the total weight of each atom in a Cacodylic acid molecule by multiplying its atomic weight by its number.

Number of Carbon atoms in Cacodylic acid: 2
Atomic weight of
Carbon (C): 12.0107
Total weight of Carbon atoms in Cacodylic acid: 12.0107 x 2 = 24.0214

Number of Hydrogen atoms in Cacodylic acid: 7
Atomic weight of Hydrogen (H): 1.008
Total weight of Hydrogen atoms in Cacodylic acid: 1.008 x 7 = 7.056

Number of Aluminum atoms in Cacodylic acid: 1
Atomic weight of Arsenic (As): 74.921595
Total weight of Aluminum atoms in Cacodylic acid: 74.921595 x 1 = 74.921595

Number of Oxygen atoms in Cacodylic acid: 2
Atomic weight of Oxygen (O): 15.9994
Total weight of Oxygen atoms in Cacodylic acid: 15.9994 x 2 = 31.9988

Step 4: Calculate the molecular weight of Cacodylic acid by adding up the total weight of all atoms.

Molecular weight of Cacodylic acid: 24.0214 (Carbon) + 7.056 (Hydrogen) + 74.921595 (Arsenic) + 31.9988 (Oxygen) = 137.997795

So the molecular weight of Cacodylic acid is 137.997795.

Cacodylic acid [(CH3)2AsOOH] Molecular Weight Calculation

## REFERENCES:

• Lanl-1: https://periodic.lanl.gov/1.shtml
• Jlab-ele006; https://education.jlab.org/itselemental/ele006.html
• Jlab-ele008: https://education.jlab.org/itselemental/ele008.html
• Jlab-ele033: https://education.jlab.org/itselemental/ele033.html
• https://www.ciaaw.org/arsenic.htm

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