What is Molecular mass with an example?

Answer

### Step-by-Step Solution:

1. **Definition of Molecular Mass**:
- Molecular mass is defined as the sum of the atomic masses of all the atoms present in a molecule of a substance.

2. **Unit of Measurement**:
- The molecular mass is expressed in atomic mass units (AMU), which is a relative unit used to measure the mass of molecules.

3. **Example Calculation**:
- Let's calculate the molecular mass of the molecule \( \text{S}_2\text{O}_4 \) (which I assume is what you meant, as \( \text{S}_4 \) is not a common molecule).
- The molecular mass can be calculated using the following formula:
\[ \text{Molecular Mass} = \text{(Number of Sulfur atoms)} \times \text{(Atomic mass of Sulfur)} + \text{(Number of Oxygen atoms)} \times \text{(Atomic mass of Oxygen)} \]

4. **Atomic Mass Values**:
- The atomic mass of Sulfur (S) is approximately \( 32.07 \, \text{AMU} \).
- The atomic mass of Oxygen (O) is approximately \( 16.00 \, \text{AMU} \).

5. **Substituting the Values**:
- For \( \text{S}_2\text{O}_4 \):
\[ \text{Molecular Mass} = (2 \times 32.07) + (4 \times 16.00) \]

6. **Calculating Each Component**:
- Calculate the contribution from Sulfur:
\[ 2 \times 32.07 = 64.14 \, \text{AMU} \]
- Calculate the contribution from Oxygen:
\[ 4 \times 16.00 = 64.00 \, \text{AMU} \]

7. **Final Calculation**:
- Now, add both contributions together:
\[ \text{Molecular Mass} = 64.14 + 64.00 = 128.14 \, \text{AMU} \]

8. **Conclusion**:
- Therefore, the molecular mass of \( \text{S}_2\text{O}_4 \) is \( 128.14 \, \text{AMU} \).