Molecular mass of `C_(3) H_(7) OH` is

Options

A. 60 u
B. 40 u
C. 30 u
D. 50 u

Answer

To calculate the molecular mass of the compound \( C_3H_7OH \) (propanol), we will follow these steps:

### Step 1: Identify the number of each type of atom in the molecular formula.
- The molecular formula \( C_3H_7OH \) indicates:
- Carbon (C): 3 atoms
- Hydrogen (H): 7 + 1 = 8 atoms (the +1 comes from the OH group)
- Oxygen (O): 1 atom

### Step 2: Find the atomic mass of each type of atom.
- The atomic masses are approximately:
- Carbon (C): 12 atomic mass units (amu)
- Hydrogen (H): 1 amu
- Oxygen (O): 16 amu

### Step 3: Calculate the total mass contributed by each type of atom.
- For Carbon:
\[ \text{Mass from Carbon} = 3 \text{ atoms} \times 12 \text{ amu/atom} = 36 \text{ amu} \]

- For Hydrogen:
\[ \text{Mass from Hydrogen} = 8 \text{ atoms} \times 1 \text{ amu/atom} = 8 \text{ amu} \]

- For Oxygen:
\[ \text{Mass from Oxygen} = 1 \text{ atom} \times 16 \text{ amu/atom} = 16 \text{ amu} \]

### Step 4: Add the total masses together to find the molecular mass.
\[ \text{Total Molecular Mass} = \text{Mass from Carbon} + \text{Mass from Hydrogen} + \text{Mass from Oxygen} \]
\[ \text{Total Molecular Mass} = 36 \text{ amu} + 8 \text{ amu} + 16 \text{ amu} = 60 \text{ amu} \]

### Conclusion:
The molecular mass of \( C_3H_7OH \) (propanol) is **60 amu**.

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