a pressure vessel contains a large volume of cn2 gas at 10atm pressure.

To calculate the number of moles of gas (CN2) in the pressure vessel, we need to use the ideal gas law equation: PV = nRT.

Where:
- P is the pressure of the gas in atmospheres (atm).
- V is the volume of the gas in liters (L).
- n is the number of moles of gas.
- R is the ideal gas constant, usually expressed as 0.0821 L·atm/(mol·K).
- T is the temperature of the gas in Kelvin (K).

Given:
- Pressure (P) = 10 atm.
- Volume (V) = Large volume (not specified).
- n = ?
- R = 0.0821 L·atm/(mol·K).

Since we don't have the value for the volume or temperature, we cannot directly calculate the number of moles (n) using the ideal gas law. We need additional information for an accurate calculation.