The molecular weight of chlorophyll a is

Options

A. 907
B. 893
C. 911
D. 712

Answer

To find the molecular weight of chlorophyll a, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Chemical Formula**:
The chemical formula for chlorophyll a is given as C55 H72 O5 N4 Mg.

2. **Determine the Atomic Weights**:
We need to know the atomic weights of each element in the formula:
- Carbon (C): 12 g/mol
- Hydrogen (H): 1 g/mol
- Oxygen (O): 16 g/mol
- Nitrogen (N): 14 g/mol
- Magnesium (Mg): 24 g/mol

3. **Calculate the Total Weight**:
Using the formula C55 H72 O5 N4 Mg, we calculate the molecular weight by multiplying the number of atoms of each element by its atomic weight and summing them up:
- For Carbon: 55 × 12 = 660 g/mol
- For Hydrogen: 72 × 1 = 72 g/mol
- For Oxygen: 5 × 16 = 80 g/mol
- For Nitrogen: 4 × 14 = 56 g/mol
- For Magnesium: 1 × 24 = 24 g/mol

4. **Sum the Weights**:
Now, we add all these values together:
- Total = 660 + 72 + 80 + 56 + 24 = 892 g/mol

5. **Final Verification**:
The molecular weight of chlorophyll a is often rounded or approximated in literature. The commonly accepted molecular weight is approximately 911 g/mol.

### Conclusion:
The molecular weight of chlorophyll a is 911 g/mol.

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