Question

Under the same conditions of temperature and pressure, which of these gases would behave most ideally: \(\mathrm{Ne}, \mathrm{N}_{2},\) or \(\mathrm{CH}_{4} ?\) Explain.

Short answer

Under the same conditions of temperature and pressure, Neon (Ne) would behave most ideally because it is the smallest and most nonpolar of the three gases.

Step-by-step solution

Understand the gas concept

In order to answer the question, it's important to first understand the concepts related to gases. An ideal gas is a hypothetical gas that perfectly fits all the assumptions of the kinetic-molecular theory. An ideal gas will exhibit more ideal behavior under lower pressure and higher temperature conditions. In reality, no gas is completely 'ideal', but they are close under normal conditions.

Evaluate Ne

Neon (Ne) is a noble gas that lacks polarity because it is a single atom with a balanced electron cloud. It is small and nonpolar, making it a likely candidate for ideal behavior. Noble gases are particularly nonreactive due to their full valence electron shells.

Evaluate N2

Nitrogen (N2) is a diatomic molecule so it's larger than Ne, but it lacks polarity because the bond between the two nitrogen atoms is nonpolar. Nitrogen's nonpolarity means it exhibits weak attractive forces, but its relatively larger size could cause deviation from ideal behavior.

Evaluate CH4

In Methane (CH4), carbon is bonded to four hydrogen atoms. The molecule is larger and more complex than the other two gases. Further, although methane is nonpolar, the hydrogen atoms can produce a minor polarization effect, meaning it has slightly higher attractive forces.

Compare and Conclude

Upon comparison, Neon (Ne) is the smallest and most nonpolar of the three gases. It will have the weakest deviations from ideal behavior. Nitrogen (N2) and Methane (CH4) are larger, and methane has slight polarizability. These factors could cause deviations from ideal behavior. Therefore, Neon would behave most ideally under the given conditions.

Key concepts

Kinetic-Molecular Theory

The kinetic-molecular theory is essential to understanding the behavior of gases. This theory provides an explanation on how gas particles move and interact. According to the theory, gas particles are constantly moving in random directions and collide with each other and with the walls of their container. During these collisions, no kinetic energy is lost; it's only transferred between particles.
- Gases are composed of small particles that are in constant, random motion. - Collisions between gas particles and in elastic, meaning no energy is lost. - There are no forces of attraction or repulsion between the particles. - The average kinetic energy of the gas particles depends on the temperature of the gas.
Under these assumptions, an ideal gas is free from inter-particle attractions and has perfectly elastic collisions. Real gases, however, sometimes deviate from these ideal behaviors due to intermolecular forces and the actual volume occupied by the gas particles, especially at high pressures or low temperatures.

Noble Gases

Noble gases, such as Neon (Ne), are known for their ideal gas behavior. These elements are unique because they have complete valence electron shells, making them chemically inert. - Noble gases are monatomic, meaning they exist as single atoms. - They are nonpolar due to their complete electron shells. - Their lack of chemical reactivity is a result of this electron configuration.
This means that noble gases do not tend to form bonds under standard conditions. Their simple atomic structure and lack of polarity make them very close to the ideal gas envisioned by the kinetic-molecular theory. Because they do not have intermolecular forces impacting them significantly, noble gases like Neon behave most ideally compared to other more complex gases.

Gas Polarity

Gas polarity refers to the separation of electric charges within a molecule, leading to a dipole moment. A molecule's shape and the difference in electronegativity between atoms contribute to its polarity. - Polar gases have uneven charge distribution, leading to dipole-dipole interactions. - Nonpolar gases, like Neon (Ne) and Nitrogen (N2), have symmetrical charge distribution, minimizing attractions between molecules. - Methane (CH4), while nonpolar, has a slightly more complex structure, which might introduce mild deviations from ideal behavior.
Nonpolar gases generally exhibit behavior closer to ideal conditions due to minimal intermolecular forces. In the context of our exercise, Neon, being a nonpolar noble gas, stands out as the best candidate for ideal behavior. This is due to its minimal interactions with neighboring atoms, allowing it to exhibit properties as defined by the kinetic-molecular theory.