The molecular weight of Copper(II) Sulfate Pentahydrate (CuSO_{4}.5H_{2}O) is 249.6866.

Copper(II) Sulfate (CuSO_{4}) is an inorganic compound of three elements: Copper, Sulfur, and Oxygen. The Pentahydrate form of Copper(II) Sulfate (CuSO_{4}.5H_{2}O, also known as Blue Vitriol) also contains 5 water molecules. The molecular weight of Copper(II) Sulfate Pentahydrate is 249.6866 which can be calculated by adding up the total weight (atomic weight multiplied by their number) of all its elements and water molecules.

**CALCULATION PROCEDURE: Copper(II) Sulfate Pentahydrate [CuSO**_{4}.5H_{2}O] Molecular Weight Calculation

_{4}.5H

_{2}O] Molecular Weight Calculation

**Step 1: Find out the chemical formula and determine constituent atoms and their number in a Copper(II) Sulfate Pentahydrate molecule. **You will know different atoms and their number in a Copper(II) Sulfate Pentahydrate molecule from the chemical formula. The chemical formula of Copper(II) Sulfate Pentahydrate is CuSO

_{4}.5H

_{2}O. From the chemical formula, you can find that one molecule of Copper(II) Sulfate Pentahydrate has one Copper (Cu) atom, one Sulfur (S) atom, four Oxygen (O) atoms, and five water molecules.

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

Atomic weight of Copper (Cu): 63.546 (Ref: Jlab-ele029)

Atomic weight of Sulfur (S): 32.066 (Ref: Jlab-ele016)

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

**Step 3: Calculate the molecular weight of Copper(II) Sulfate Pentahydrate by adding the total weight of all atoms. **

Number of Copper atoms in Copper(II) Sulfate Pentahydrate: 1

Atomic weight of Copper: 63.546

Total weight of Copper atoms in Copper(II) Sulfate Pentahydrate: 63.546 x 1 = 63.546

Number of Sulfur (S) atoms in Copper(II) Sulfate Pentahydrate: 1

Atomic weight of Sulfur: 32.066

Total weight of Sulfur atoms in Copper(II) Sulfate Pentahydrate: 32.066 x 1 = 32.066

Number of Oxygen (O) atoms in Copper(II) Sulfate Pentahydrate: 4

Atomic weight of Oxygen: 15.9994

Total weight of Oxygen atoms in Copper(II) Sulfate Pentahydrate: 15.9994 x 4 = 63.9976

Number of water (H_{2}O) molecules in Potassium antimonyl tartrate trihydrate: 5

Molecular weight of water: 18.0154

Total weight of water in Potassium antimonyl tartrate trihydrate: 18.0154 x 5 = 90.077

**Step 4: Calculate the molecular weight of Copper(II) Sulfate Pentahydrate by adding up the total weight of all atoms. **

Molecular weight of Copper(II) Sulfate Pentahydrate : 63.546 (Copper) + 32.066 (Sulfur) + 63.9976 (Oxygen) + 90.077 (Water) = 249.6866

So the molecular weight of Copper(II) Sulfate Pentahydrate is 249.6866.

Copper(II) Sulfate Pentahydrate [CuSO_{4}.5H_{2}O] Molecular Weight Calculation

Molecular weight of Copper(II) Sulfate Pentahydrate (CuSO_{4}.5H_{2}O) | |||

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

Copper (Cu) | 1 | 63.546 | 63.546 |

Sulfur (S) | 1 | 32.066 | 32.066 |

Oxygen (O) | 4 | 15.9994 | 63.9976 |

Water (H_{2}O) | 5 | 18.0154 | 90.077 |

Molecular weight of Copper(II) Sulfate Pentahydrate (CuSO_{4}.5H_{2}O): | 249.6866 |

## REFERENCES:

- Jlab-ele029: https://education.jlab.org/itselemental/ele029.html
- Jlab-ele016: https://education.jlab.org/itselemental/ele016.html
- Jlab-ele008: https://education.jlab.org/itselemental/ele008.html