The molecular weight of Phenylalanine [C_{9}H_{11}NO_{2}] is 165.18984.

Phenylalanine (C_{5}H_{11}NO_{2}) is an organic compound of four elements: Carbon, Hydrogen, Nitrogen, and Oxygen. The molecular weight of Phenylalanine is 165.18984 which can be calculated by adding up the total weight (atomic weight multiplied by their number) of all its elements.

**CALCULATION PROCEDURE: Phenylalanine [C**_{9}H_{11}NO_{2}] Molecular Weight Calculation

_{9}H

_{11}NO

_{2}] Molecular Weight Calculation

**Step 1: Find out the chemical formula and determine constituent atoms and their number in a Phenylalanine molecule.**From the chemical formula, you will know different atoms and their number in a Phenylalanine molecule. The chemical formula of Phenylalanine is C

_{9}H

_{11}NO

_{2}. From the chemical formula of Phenylalanine, you can find that one molecule of Phenylalanine consists of five Carbon (C) atoms, eleven Hydrogen (H) atoms, one Nitrogen (N) atom, and two Oxygen 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 Nitrogen (N): 14.00674 (Ref: Jlab-ele007)

Atomic weight of Oxygen (O): 15.9994 (Ref: Jlab-ele008)

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

Number of Carbon atoms in Phenylalanine: 9

Atomic weight of Carbon (C): 12.0107

Total weight of Carbon atoms in Phenylalanine: 12.0107 x 9 = 108.0963

Number of Hydrogen atoms in Phenylalanine: 11

Atomic weight of Hydrogen (H): 1.008

Total weight of Hydrogen atoms in Phenylalanine: 1.008 x 11 = 11.088

Number of Nitrogen atoms in Phenylalanine: 1

Atomic weight of Nitrogen (N): 14.00674

Total weight of Nitrogen atoms in Phenylalanine: 14.00674 x 1 = 14.00674

Number of Oxygen atoms in Phenylalanine: 2

Atomic weight of Oxygen (O): 15.9994

Total weight of Oxygen atoms in Phenylalanine: 15.9994 x 2 = 31.9988

**Step 4: Calculate the molecular weight of Phenylalanine by adding up the total weight of all atoms.**

Molecular weight of Phenylalanine: 108.0963 (Carbon) + 11.088 (Hydrogen) + 14.00674 (Nitrogen) + 31.9988 (Oxygen) = 165.18984

So the molecular weight of Phenylalanine is 165.18984.

Phenylalanine(C_{9}H_{11}NO_{2}) Molecular Weight Calculation

Molecular weight of Phenylalanine (C_{9}H_{11}NO_{2}) | |||

Constituent atoms | Number of each atom | Atomic weight | Total weight |

Carbon (C) | 9 | 12.0107 | 108.0963 |

Hydrogen (H) | 11 | 1.008 | 11.088 |

Nitrogen (N) | 1 | 14.00674 | 14.00674 |

Oxygen (O) | 2 | 15.9994 | 31.9988 |

Molecular weight of Phenylalanine (C_{9}H_{11}NO_{2}): | 165.18984 |

## REFERENCES:

- Lanl-1: https://periodic.lanl.gov/1.shtml
- Jlab-ele006: https://education.jlab.org/itselemental/ele006.html
- Jlab-ele007: https://education.jlab.org/itselemental/ele007.html
- Jlab-ele008: https://education.jlab.org/itselemental/ele008.html