<< Chapter < Page Chapter >> Page >

Introduction

We performed “chemical algebra” or stoichiometric calculations in the early Concept Development Studies, using a balanced chemical equation to determine the masses or numbers of moles of product created from the masses or numbers of moles of the reactants. For example, if we burn methane gas, CH 4 (g), in excess oxygen, the reaction

CH 4 (g) + 2O 2 (g) → CO 2 (g) + 2 H 2 O(g)

occurs, and we assumed, correctly in this case, that the number of moles of CO 2 (g) produced is equal the number of moles of CH 4 (g) we start with. This follows directly from the balanced equation but requires us to assume that all of the CH 4 is converted into CO 2 during the reaction.

From our study of phase transitions and solubility, we have learned the concept of equilibrium. We observed that, in the transition from one phase to another for a substance, both phases are found to coexist under certain conditions, and we refer to this as phase equilibrium. For example, when a liquid is in equilibrium with its vapor, not all of the liquid converts into vapor and not all of the vapor converts into the liquid. In this case, we would not be able to calculate the number of moles of vapor from the number of moles of liquid.

It should not surprise us that these same concepts of equilibrium used to describe the coexistence of phases can apply to chemical reactions as well. In Reaction (1) above, therefore, we should determine whether the reaction actually produces exactly one mole of CO 2 for every mole of CH 4 we start with or whether we wind up with an equilibrium mixture containing both CO 2 and CH 4 . In this case, the answer is that the reaction does “go to completion,” meaning that with very high accuracy we can assume that every CH 4 reacts to produce a CO 2 . However, in studying many reactions, we will find that different reactions provide us with varying outcomes. In many cases, virtually all reactants are consumed, producing the amount of product predicted by stoichiometric calculation. In many other cases, substantial amounts of reactant are still present along with product when the reaction achieves equilibrium. And in other cases, almost no product is present at equilibrium. Our goal will be to understand, describe, and predict the reaction equilibrium.

An important corollary to this goal is to attempt to control the equilibrium. We will find that varying the conditions under which the reaction occurs can vary the amounts of reactants and products present at equilibrium. We will develop a general principle for predicting how the reaction conditions affect the amount of product produced at equilibrium.

Foundation

In beginning our study of the reactions of gases, we will assume a knowledge of the physical properties of gases as described by the Ideal Gas Law and an understanding of these properties as given by the postulates and conclusions of the Kinetic Molecular Theory. We assume that we have developed a dynamic model of phase equilibrium in terms of competing rates. We will also assume an understanding of the bonding, structure, and properties of individual molecules.

Questions & Answers

what is mutation
Janga Reply
what is a cell
Sifune Reply
how is urine form
Sifune
what is antagonism?
mahase Reply
classification of plants, gymnosperm features.
Linsy Reply
what is the features of gymnosperm
Linsy
how many types of solid did we have
Samuel Reply
what is an ionic bond
Samuel
What is Atoms
Daprince Reply
what is fallopian tube
Merolyn
what is bladder
Merolyn
what's bulbourethral gland
Eduek Reply
urine is formed in the nephron of the renal medulla in the kidney. It starts from filtration, then selective reabsorption and finally secretion
onuoha Reply
State the evolution relation and relevance between endoplasmic reticulum and cytoskeleton as it relates to cell.
Jeremiah
what is heart
Konadu Reply
how is urine formed in human
Konadu
how is urine formed in human
Rahma
what is the diference between a cavity and a canal
Pelagie Reply
what is the causative agent of malaria
Diamond
malaria is caused by an insect called mosquito.
Naomi
Malaria is cause by female anopheles mosquito
Isaac
Malaria is caused by plasmodium Female anopheles mosquitoe is d carrier
Olalekan
a canal is more needed in a root but a cavity is a bad effect
Commander
what are pathogens
Don Reply
In biology, a pathogen (Greek: πάθος pathos "suffering", "passion" and -γενής -genēs "producer of") in the oldest and broadest sense, is anything that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ. The term pathogen came into use in the 1880s.[1][2
Zainab
A virus
Commander
Definition of respiration
Muhsin Reply
respiration is the process in which we breath in oxygen and breath out carbon dioxide
Achor
how are lungs work
Commander
where does digestion begins
Achiri Reply
in the mouth
EZEKIEL
what are the functions of follicle stimulating harmones?
Rashima Reply
stimulates the follicle to release the mature ovum into the oviduct
Davonte
what are the functions of Endocrine and pituitary gland
Chinaza
endocrine secrete hormone and regulate body process
Achor
while pituitary gland is an example of endocrine system and it's found in the Brain
Achor
what's biology?
Egbodo Reply
Biology is the study of living organisms, divided into many specialized field that cover their morphology, physiology,anatomy, behaviour,origin and distribution.
Lisah
biology is the study of life.
Alfreda
Biology is the study of how living organisms live and survive in a specific environment
Sifune
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




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
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Concept development studies in chemistry 2013' conversation and receive update notifications?

Ask