# 0.16 Equilibrium and the second law of thermodynamics  (Page 11/11)

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${H}_{2}\left(g\right)+{I}_{2}\left(g\right)\to 2HI\left(g\right)$
$Q=\frac{{P}_{HI}^{2}}{{P}_{{H}_{2}}{P}_{{I}_{2}}}$

It is important to note that the partial pressures in $Q$ need not be the equilibrium partial pressures. However, if the pressures in $Q$ are the equilibrium partial pressures, then $Q$ has the same value as ${K}_{p}$ , the equilibrium constant, by definition. Moreover, if the pressuresare at equilibrium, we know that $\Delta (G)=0$ . If we look back at [link] , we can conclude that

$\Delta ({G}^{°})=-(RT\ln {K}_{p})$

This is an exceptionally important relationship, because it relates two very different observations.To understand this significance, consider first the case where $\Delta ({G}^{°})< 0$ . We have previously reasoned that, in this case, the reactionequilibrium will favor the products. From [link] we can note that, if $\Delta ({G}^{°})< 0$ , it must be that ${K}_{p}> 1$ . Furthermore, if $\Delta ({G}^{°})$ is a large negative number, ${K}_{p}$ is a very large number. By contrast, if $\Delta ({G}^{°})$ is a large positive number, ${K}_{p}$ will be a very small (though positive) number much less than 1. In this case, the reactants will be strongly favored atequilibrium.

Note that the thermodynamic description of equilibrium and the dynamic description of equilibrium arecomplementary. Both predict the same equilibrium. In general, the thermodynamic arguments give us an understanding of the conditionsunder which equilibrium occurs, and the dynamic arguments help us understand how the equilibrium conditions are achieved.

## Review and discussion questions

Each possible sequence of the 52 cards in a deck is equally probable. However, when you shuffle a deck and thenexamine the sequence, the deck is never ordered. Explain why in terms of microstates, macrostates, and entropy.

Assess the validity of the statement, "In all spontaneous processes, the system moves toward a state of lowestenergy." Correct any errors you identify.

In each case, determine whether spontaneity is expected at low temperature, high temperature, any temperature, orno temperature:

$\Delta ({H}^{°})> 0$ , $\Delta ({S}^{°})> 0$

$\Delta ({H}^{°})< 0$ , $\Delta ({S}^{°})> 0$

$\Delta ({H}^{°})> 0$ , $\Delta ({S}^{°})< 0$

$\Delta ({H}^{°})< 0$ , $\Delta ({S}^{°})< 0$

Using thermodynamic equilibrium arguments, explain why a substance with weaker intermolecular forces has agreater vapor pressure than one with stronger intermolecular forces.

Why does the entropy of a gas increase as the volume of the gas increases? Why does the entropy decrease as thepressure increases?

For each of the following reactions, calculate the values of $\Delta ({S}^{°})$ , $\Delta ({H}^{°})$ , and $\Delta ({G}^{°})$ at $T=298K$ and use these to predict whether equilibrium will favor products or reactants at $T=298K$ . Also calculate ${K}_{p}$ .

$2CO\left(g\right)+{O}_{2}\left(g\right)\to 2C{O}_{2}\left(g\right)$

${O}_{3}\left(g\right)+NO\left(g\right)\to N{O}_{2}\left(g\right)+{O}_{2}\left(g\right)$

$2{O}_{3}\left(g\right)\to 3{O}_{2}\left(g\right)$

Predict the sign of the entropy for the reaction $2{H}_{2}\left(g\right)+{O}_{2}\left(g\right)\to 2{H}_{2}O\left(g\right)$ Give an explanation, based on entropy and the Second Law, of why this reaction occurs spontaneously.

For the reaction ${H}_{2}\left(g\right)\to 2H\left(g\right)$ , predict the sign of both $\Delta ({H}^{°})$ and $\Delta ({S}^{°})$ . Should this reaction be spontaneous at high temperature or at lowtemperature? Explain.

For each of the reactions in [link] , predict whether increases in temperature will shift the reaction equilibrium more towardsproducts or more towards reactants.

Using [link] and [link] , show that for a given set of initial partial pressures where $Q$ is larger than ${K}_{p}$ , the reaction will spontaneously create more reactants. Also showthat if $Q$ is smaller than ${K}_{p}$ , the reaction will spontaneously create more products.

where we get a research paper on Nano chemistry....?
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
what about nanotechnology for water purification
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
why we need to study biomolecules, molecular biology in nanotechnology?
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
why?
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
how did you get the value of 2000N.What calculations are needed to arrive at it
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