In the gas equation, PV = nRT

Options

A. V denotes volume of one mole
B. n is the number of molecules of a gas
C. n moles of gas have volume V
D. P is pressure of gas when only one mole of gas is present

Explanation

To solve the question regarding the gas equation \( PV = nRT \) and to identify which statement is correct, we can break it down step by step.

### Step 1: Understand the Ideal Gas Equation
The equation \( PV = nRT \) is known as the ideal gas equation. It relates the pressure (P), volume (V), number of moles (n), universal gas constant (R), and temperature (T) of an ideal gas.

### Step 2: Identify Each Variable
- **P**: Pressure of the gas (in atmospheres, pascals, etc.)
- **V**: Volume of the gas (in liters, cubic meters, etc.)
- **n**: Number of moles of the gas.
- **R**: Universal gas constant, which has a value of approximately \( 0.0821 \, \text{L atm K}^{-1} \text{mol}^{-1} \) or \( 8.314 \, \text{J K}^{-1} \text{mol}^{-1} \).
- **T**: Temperature of the gas (in Kelvin).

### Step 3: Analyze the Statements
Now, we need to evaluate the statements provided in the question regarding the ideal gas equation:

1. **V denotes volume of 1 mole**: This statement is incorrect. The volume \( V \) in the equation is for \( n \) moles, not just 1 mole.

2. **N is the number of molecules**: This statement is also incorrect. \( n \) represents the number of moles, not the number of molecules. The number of molecules can be calculated from moles using Avogadro's number.

3. **N represents moles of a gas that occupy the volume V**: This statement is correct. \( n \) is indeed the number of moles of gas that occupy the volume \( V \).

4. **P is the pressure of the gas when you have 1 mole of gas present**: This statement is incorrect. The pressure \( P \) is defined for \( n \) moles of gas, not just for 1 mole.

### Conclusion
Based on the analysis, the correct statement is:
- **N represents moles of a gas that occupy the volume V**.

### Final Answer
The correct statement related to the gas equation \( PV = nRT \) is that \( n \) represents moles of a gas that occupy the volume \( V \).

---