The percentage of nitrogen in urea is:

Options

A. 46
B. 23
C. 48
D. 52

Answer

To find the percentage of nitrogen in urea (NH2CO), we will follow these steps:

### Step 1: Determine the molecular formula of urea.
Urea has the molecular formula NH2CO, which consists of:
- 2 Nitrogen (N) atoms
- 1 Carbon (C) atom
- 1 Oxygen (O) atom
- 4 Hydrogen (H) atoms

### Step 2: Calculate the molar mass of urea.
To find the molar mass, we need to sum the atomic masses of all the atoms in the molecular formula:
- Nitrogen (N): 14 g/mol (2 atoms) = 2 × 14 = 28 g/mol
- Carbon (C): 12 g/mol (1 atom) = 1 × 12 = 12 g/mol
- Oxygen (O): 16 g/mol (1 atom) = 1 × 16 = 16 g/mol
- Hydrogen (H): 1 g/mol (4 atoms) = 4 × 1 = 4 g/mol

Now, we add these together:
\[ \text{Total molar mass} = 28 + 12 + 16 + 4 = 60 \text{ g/mol} \]

### Step 3: Calculate the total mass of nitrogen in urea.
The total mass of nitrogen in urea is:
\[ \text{Mass of N} = 28 \text{ g/mol} \]

### Step 4: Calculate the percentage of nitrogen in urea.
To find the percentage of nitrogen, we use the formula:
\[ \text{Percentage of N} = \left( \frac{\text{Mass of N}}{\text{Total molar mass of urea}} \right) \times 100 \]
Substituting the values:
\[ \text{Percentage of N} = \left( \frac{28}{60} \right) \times 100 \]
\[ \text{Percentage of N} = 0.4667 \times 100 \approx 46.67\% \]

### Final Answer:
The percentage of nitrogen in urea is approximately **46.67%**.

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