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If the molecules remain the same size but occupy a much larger space, there is only one possible conclusion: the molecules in the gas must be much farther apart in the gas than in the liquid. These distances must be very large. To see this, imagine a crowded elevator completely filled with people who are elbow-to-elbow. When the door opens, imagine that they now enter a room which is 1000 times larger than the elevator. Assuming that the people spread out, think about the large distances between people is this huge room. The space between people is much larger than the size of each person. In fact, the space is so large that the sizes of the individual people become insignificant. In the crowded elevator, the sizes of the people matters. But in the open room, the distances between people are so large that the distances between people are the same whether they are adults or children.

And this must be true of molecules as well. In a gas, the spaces between molecules must be very large, so large that the size of each molecule is insignificant. If we combine this conclusion with our conclusion from Observation 1, we can begin to build a model to explain why the Ideal Gas Law works provided that the gas density is not too high. At reasonable gas densities, the molecules are so far apart that the differences in size, shape, and structure of individual molecules are unimportant.

Observation 3: dalton’s law of partial pressures

An interesting observation related to the Ideal Gas Law is Dalton’s Law of Partial Pressures. We observed this in the previous Concept Development Study. Dalton’s Law described the pressure of a mixture of gases. Let’s say we mix oxygen and nitrogen, as in our atmosphere, and let’s take them in the same approximate proportions as in our atmosphere. In a container of fixed volume, we can put in enough nitrogen to create a pressure of 0.8 atm. We could also put in enough oxygen to create a pressure of 0.2 atm. If we take that same amount of nitrogen and that same amount of oxygen and put them both in the same fixed volume container, we find that the pressure is 1.0 atm. In other words, the total pressure of the gas is equal to the sum of the individual pressures of the gases, called the “partial pressures.”

This observation tells us that the oxygen molecules create the same 0.2 atm pressure whether the nitrogen molecules are present or not. And the same is true of the nitrogen molecules, which create a pressure of 0.8 atm whether or not the oxygen molecules are present. This is a striking observation. It means that the oxygen molecules in a mixture with nitrogen molecules must move in exactly the same way that they would if the nitrogen molecules were not there. It appears from our observations that the motions of the nitrogen molecules and the oxygen molecules do not affect each other at all.

We need to think about why this would be true. If we add this conclusion to the conclusions of Observations 1 and 2, we can see that the molecules in a gas are very far apart from one another and they do not affect each other’s movements. This makes sense: if the molecules are so far apart from one another, then they never affect each other. More specifically, they never (or almost never) exert forces on each other or run into each other.

Questions & Answers

who was the first nanotechnologist
Lizzy Reply
technologist's thinker father is Richard Feynman but the literature first user scientist Nario Tagunichi.
Norio Taniguchi
I need help
anyone have book of Abdel Salam Hamdy Makhlouf book in pdf Fundamentals of Nanoparticles: Classifications, Synthesis
Naeem Reply
what happen with The nano material on The deep space.?
pedro Reply
It could change the whole space science.
the characteristics of nano materials can be studied by solving which equation?
sibaram Reply
plz answer fast
synthesis of nano materials by chemical reaction taking place in aqueous solvents under high temperature and pressure is call?
hydrothermal synthesis
how can chip be made from sand
Eke Reply
is this allso about nanoscale material
are nano particles real
Missy Reply
Hello, if I study Physics teacher in bachelor, can I study Nanotechnology in master?
Lale Reply
no can't
where is the latest information on a no technology how can I find it
where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
Application of nanotechnology in medicine
has a lot of application modern world
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
yes that's correct
I think
Nasa has use it in the 60's, copper as water purification in the moon travel.
nanocopper obvius
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
STM - Scanning Tunneling Microscope.
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Source:  OpenStax, Concept development studies in chemistry 2013. OpenStax CNX. Oct 07, 2013 Download for free at http://legacy.cnx.org/content/col11579/1.1
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