Question

Which gas would behave more ideally at the same conditions of pressure and temperature: \(\mathrm{CO}\) or \(\mathrm{N}_{2}\) ? Why?

Short answer

N2 would behave more ideally than CO under the same conditions of pressure and temperature. This is because N2 is a nonpolar molecule with fewer intermolecular forces, which more closely adheres to the assumptions of the ideal gas law.

Step-by-step solution

Understand the Ideal Gas Law

The ideal gas law is given by the equation \(PV = nRT\), where P is the pressure, V is the volume, n is the number of moles, R is the universal gas constant, and T is the temperature. This equation assumes that gas molecules behave independently, with no interactions between them, which is true for highly diluted gases or conditions of high temperature and low pressure.

Compare Molecular Properties of CO and N2

CO (carbon monoxide) is a polar molecule because of the difference in electronegativity between the carbon and oxygen atoms. On the other hand, N2 (nitrogen) is a nonpolar molecule, as it consists of two nitrogen atoms with equal electronegativity.

Link Molecular Properties to Ideal Behavior

In an ideal gas, the molecules do not interact with each other. This is more likely to occur for nonpolar molecules, as they will not experience the intermolecular forces that polar molecules do (such as dipole-dipole interactions). Since N2 is a nonpolar molecule and CO is a polar molecule, N2 will have fewer intermolecular forces acting between its molecules.

Determine the Gas with More Ideal Behavior

Based on the molecular properties of CO and N2 and how they relate to ideal gas behavior, we can conclude that the gas N2 would behave more ideally than CO under the same conditions of pressure and temperature. This is because N2 is a nonpolar molecule with fewer intermolecular forces, which more closely adheres to the assumptions of the ideal gas law.

Key concepts

Molecular Properties

Molecular properties play a crucial role in determining how different gases behave under various conditions. In the case of the problem, the gases in question are carbon monoxide (CO) and nitrogen (N extsubscript{2}). Carbon monoxide is a polar molecule, meaning it has a permanent dipole due to the unequal sharing of electrons between the carbon and oxygen atoms. This polarity causes CO molecules to have partial positive and negative charges.
In contrast, nitrogen, N extsubscript{2}, is nonpolar. It consists of two nitrogen atoms sharing electrons equally, resulting in no permanent dipole. Nonpolar molecules like N extsubscript{2} do not have regions of partial charge, making them less interactive compared to polar molecules like CO.

These molecular properties affect whether a gas behaves according to the ideal gas law. Nonpolar molecules are closer to the ideal gas behavior, as they lack strong intermolecular attractions that affect their motion and energy distribution.

Gas Behavior

Gas behavior is significantly influenced by the molecular properties as discussed above. According to the ideal gas law equation, \(PV = nRT\), ideal gases are considered to have no interactions between them. However, this is a simplified model. In reality, gases have intermolecular forces that influence their actions under certain conditions.
At the same conditions of pressure and temperature, gases are expected to follow this law more closely if they experience minimal intermolecular forces. This is important, for example, in high-temperature and low-pressure scenarios where gases tend to spread out and interact less.

Given these conditions, nitrogen gas (N extsubscript{2}), being nonpolar, behaves more ideally compared to carbon monoxide (CO), as nonpolar gases have minimal intermolecular interactions. Polar gases like CO exhibit deviations because their molecules are attracted to each other, impacting the way they move and occupy space.

Intermolecular Forces

Intermolecular forces are the forces that exist between molecules, affecting their arrangement and behavior in different conditions. In the context of the ideal gas law, these forces can cause gases to deviate from ideal behavior. There are different types of intermolecular forces, including dipole-dipole interactions, London dispersion forces, and hydrogen bonding.
Polar molecules like CO experience dipole-dipole forces, which occur because the positive end of one molecule is attracted to the negative end of another. This creates additional energy barriers that prevent the gas from behaving ideally.

On the other hand, N extsubscript{2}, being a nonpolar molecule, only experiences weak London dispersion forces. These are temporary attractive forces that arise from moments of induced dipoles in the molecules. These weaker forces mean N extsubscript{2} molecules can more freely interact and spread out as described by the ideal gas law, making it behave more ideally than CO.