"The planets Uranus and Neptune are so far from the Sun that temperatures are low enough for atmospheric methane, CH4, to condense and form clouds. How is it possible for methane, a nonpolar substance, to exist in this liquid state?"
I want to say it's because nonpolar substances still have London dispersion forces, so the methane molecules are attracted to each other enough to stay in cloud form. Other than that, I'm not sure why being nonpolar affects methane's ability to form clouds.
Thanks!
I know this is a late reply but who cares ¯\_(ツ)_/¯
Methane has London dispersion forces, they are weak. Because of this Methane condenses to a liquid at -161.85 celsius. Due to Uranus and Neptune being so far from the Sun, they are -224 and -214 celsius respectful (Uranus being the coldest planet in our solar system) So methane would be able to condense.
https://courses.lumenlearning.com/wsu-sandbox2/chapter/intermolecular-forces/
Look particularly at Figure 5 and related text.
The reason why Methane being nonpolar and having london dispersion forces is important, is because low london dispersion forces results in a low boiling point. Boiling points are always equal to the condensation point. If Methane exhibited a different type of intermolecular force then the boiling point would be condensation point would be higher, resulting in methane condensing at a different temperature (perhaps even on Earth)
Well, well, well, it seems we have ourselves a cloudy question! Let's get into it, shall we?
You're absolutely right! Methane, being a nonpolar molecule, doesn't have those fancy-dancy dipole-dipole attractions like its polar friends. However, it's not left completely high and dry when it comes to forming those cool methane clouds on Uranus and Neptune.
Enter the unsung hero of intermolecular attractions: the London dispersion forces! Also known as Van der Waals forces, these are the result of temporary fluctuations in electron distribution that create a temporary, weak attraction between molecules.
Now, even though methane is nonpolar, it still has a distribution of electrons that can cause these fleeting attractions. As a result, the methane molecules join forces (or rather, weakly bond) through these London dispersion forces, which allows them to clump together and form those lovely methane clouds we see on Uranus and Neptune.
So, remember, even in the cold depths of space, where the Sun barely shines, nonpolar molecules like methane can still find a way to make connections and form clouds. Isn't chemistry just full of surprises?
Hope that clears things up for you! Keep those questions coming, and I'll keep the humor flowing like a methane cloud on a distant planet.
You are partially correct in your understanding. The low temperature on planets like Uranus and Neptune allows methane to condense and form clouds. However, the reason why nonpolar substances like methane can exist in a liquid state is not solely due to London dispersion forces.
Methane (CH4) is a nonpolar molecule, meaning it has no net dipole moment and the electron density is distributed evenly around the molecule. This lack of charge separation makes methane molecules unable to form hydrogen bonds, which are responsible for the strong attractions between molecules in compounds like water.
However, even though nonpolar molecules like methane do not have hydrogen bonding, they still experience intermolecular forces. One of the most significant intermolecular forces for nonpolar molecules is London dispersion forces, also known as van der Waals forces. These forces arise from temporary fluctuations in electron distribution within molecules, creating momentarily uneven electron distributions. This causes temporary partial positive and negative charges, which can induce similar charges in neighboring molecules, leading to attractive forces.
In the case of methane, London dispersion forces are sufficient to hold the molecules together when the temperature is low enough for them to condense into a liquid. While the strength of these forces is generally weaker than hydrogen bonding, under the extreme conditions of Uranus and Neptune with extremely low temperatures and high pressures, these forces become significant enough to allow methane to exist as a liquid and form clouds.
So, in summary, while nonpolar substances like methane lack hydrogen bonding, they can still exhibit intermolecular forces, such as London dispersion forces, that are strong enough to enable them to condense and form clouds when the temperature and pressure conditions are suitable.