How many hydrogen atoms are present in 60 a.m.u. of ethane ?

Answer

To determine how many hydrogen atoms are present in 60 a.m.u. of ethane (C2H6), we can follow these steps:

### Step-by-Step Solution:

1. **Determine the Molecular Mass of Ethane (C2H6)**:
- The molecular formula of ethane is C2H6.
- The atomic mass of carbon (C) is approximately 12 a.m.u.
- The atomic mass of hydrogen (H) is approximately 1 a.m.u.
- Calculate the molecular mass:
\[ \text{Molecular mass of C2H6} = (2 \times 12) + (6 \times 1) = 24 + 6 = 30 \text{ a.m.u.} \]

2. **Understand the Relationship Between Mass and Moles**:
- 1 mole of ethane (C2H6) has a mass of 30 a.m.u. and contains 6 hydrogen atoms.
- Therefore, 30 a.m.u. of ethane corresponds to 6 hydrogen atoms.

3. **Calculate the Number of Hydrogen Atoms in 60 a.m.u. of Ethane**:
- We need to find out how many hydrogen atoms are present in 60 a.m.u. of ethane.
- Since 30 a.m.u. of ethane contains 6 hydrogen atoms, we can set up a proportion:
\[ \text{If } 30 \text{ a.m.u.} \text{ has } 6 \text{ H atoms, then } 60 \text{ a.m.u. has } x \text{ H atoms.} \]
- Using the ratio:
\[ \frac{6 \text{ H atoms}}{30 \text{ a.m.u.}} = \frac{x \text{ H atoms}}{60 \text{ a.m.u.}} \]
- Cross-multiplying gives:
\[ 6 \times 60 = 30 \times x \implies 360 = 30x \implies x = \frac{360}{30} = 12 \]

4. **Conclusion**:
- Therefore, there are **12 hydrogen atoms** present in 60 a.m.u. of ethane.