Gram molecular mass of `CH_4` is

Options

A. 16 g
B. 16 u
C. 32 g
D. 32 u

Answer

To find the gram molecular mass of methane (CH₄), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the components of the molecule**:
- Methane (CH₄) consists of one carbon (C) atom and four hydrogen (H) atoms.

2. **Find the atomic masses of the elements**:
- The atomic mass of carbon (C) is approximately 12 u (unified atomic mass units).
- The atomic mass of hydrogen (H) is approximately 1 u.

3. **Calculate the total mass contributed by each element**:
- For carbon:
\[ \text{Mass from Carbon} = \text{Atomic mass of C} \times \text{Number of C atoms} = 12 \, \text{u} \times 1 = 12 \, \text{u} \]
- For hydrogen:
\[ \text{Mass from Hydrogen} = \text{Atomic mass of H} \times \text{Number of H atoms} = 1 \, \text{u} \times 4 = 4 \, \text{u} \]

4. **Sum the total mass to find the molecular mass**:
- Total molecular mass of CH₄:
\[ \text{Molecular mass of CH₄} = \text{Mass from Carbon} + \text{Mass from Hydrogen} = 12 \, \text{u} + 4 \, \text{u} = 16 \, \text{u} \]

5. **Convert the molecular mass to gram molecular mass**:
- The gram molecular mass is numerically equal to the molecular mass but expressed in grams. Therefore, the gram molecular mass of CH₄ is:
\[ \text{Gram molecular mass of CH₄} = 16 \, \text{g} \]

### Final Answer:
The gram molecular mass of CH₄ is **16 grams**.

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