Chemistry

The key here is that dissociation increases the total number of gas particles, which directly increases pressure. Start by finding how many moles of $\text{N}_2$ you have, then account for the fact that 30% breaks apart into individual N atoms—each $\text{N}_2$ molecule that dissociates becomes 2 atoms, so the particle count jumps. Once you know the total number of moles of gas particles present, use the ideal gas law $PV = nRT$ to find pressure.

The key here is that dissociation increases the total number of gas particles, which directly increases pressure. Start by finding how many moles of $\text{N}_2$ you have, then account for the fact that 30% breaks apart into individual N atoms—each $\text{N}_2$ molecule that dissociates becomes 2 atoms, so the particle count jumps. Once you know the total number of moles of gas particles present, use the ideal gas law $PV = nRT$ to find pressure.