Why is \(\mathrm{N}_{2}\) a gas at room temperature? Explain why lowering the temperature allows for liquid \(\mathrm{N}_{2}\) to form.

Intermolecular forces are the forces of attraction (or repulsion) between particles (atoms or molecules) within a substance. The strength of these forces determines the phase of a substance at a given temperature. Generally, stronger intermolecular forces result in a more solid-like state, while weaker forces result in a gaseous state.

Nitrogen molecules (\(\mathrm{N}_{2}\)) consist of two nitrogen atoms held together by a strong triple covalent bond. However, the intermolecular forces between these molecules are relatively weak. This is because nitrogen, being a non-polar molecule, only experiences London dispersion forces, which are the weakest type of intermolecular force. At room temperature, these weak intermolecular forces are insufficient to hold the nitrogen molecules together in a solid or liquid state, and thus nitrogen exists as a gas.

When the temperature of a substance is lowered, its kinetic energy (the energy possessed by particles due to their motion) also decreases. As the kinetic energy decreases, the particles move more slowly, and the attractive forces between them become more significant in comparison.

As the temperature of nitrogen gas is reduced, its kinetic energy decreases, and the particles slow down enough that the weak London dispersion forces between nitrogen molecules can hold them closer together. When the temperature reaches a low enough point (approximately -195.8°C or -320.4°F), the nitrogen molecules are sufficiently close to form liquid nitrogen. This process is known as condensation. Overall, the reason nitrogen exists as a gas at room temperature is due to its weak intermolecular forces, specifically London dispersion forces. However, by lowering the temperature, the kinetic energy of the molecules decreases, allowing these weak forces to become more significant and enabling the formation of liquid nitrogen.