Aug
12
How Can I Build Chemistry In My Current Relationship?
Filed Under Physical Chemistry | Leave a Comment
A lot of people are under the misconception that chemistry between two people happens automatically. Chances are real slim to create chemistry with someone when none exists in the first place or there\’s very little to work with.
The first thing you have to know is what exactly is chemistry.
It can be pretty difficult to find chemistry if you\’ve never had it with a person, but if you have had it with someone you know exactly what chemistry is. The idea that pops into your head or floats into your unconscious is one that makes you feel that the two of you should be together no matter what. It is something that tells you that this feels just right… perhaps you two were meant to be together.
It can begin with the feeling that the two of you feel completely at ease with each other, and that you two have an uncanny physical attraction toward each other. While this attraction might be due to each other\’s looks, physical looks, in reality it comes down to a mental game. Game is probably the wrong word to use… Let\’s just say it could be a condition of your mental state. It could come down to something as simple as each having the same pet peeves, each knowing what the other is going to say before they say it and so on. Having the same beliefs, even the same dreams of what the future will hold for you can be the start of the chemistry you\’re looking for.
To be honest, before creating chemistry with someone you need to spend time with them and create a relationship of some type with this person. Needless to say this goes beyond the first, second, or even third date and have once you have spent more time together.
Look for a good topic or even something that you both enjoy doing to give you good conversation to start with. Good conversation is the key…if you don\’t have it, chances are you won\’t get that chemistry simmering and moving up to a boil. Don\’t start with politics or religion…yes…it\’s just like our parents taught us not to speak of these issues outside the circle of good friends. Save those topics until you become better acquainted. You don\’t need a high-stress point when you just are getting started. Start with a topic or subject you both can have fun with.
One big thing - if you have a great sense of humor - use it! And, hope the other person has one also. Laughter can break down many walls and help people to bond much more easily. And..keep the humor clean and not obscene, and without prejudice. I guess that\’s pretty obvious.
One other thing that is obvious: act like yourself. Don\’t try to be someone you\’re not. To have true chemistry with someone they have to know the real you. Don\’t keep all your opinions to yourself. Make it a point to share some of your thoughts and feelings about important issues…these issues may be also be important your partner. It\’s all up to the way you converse with the person as to whether that elusive chemistry can begin simmering.
Try to plan exciting dates, studies have shown that couples who meet in exciting situations tend to find each other more attractive. This pattern works because the mind associates any excitement with the person we are with at the time and mistakes it for physical attraction. You can make use of this feeling by planning a date that will get the adrenaline pumping… a scary movie, take a roller coaster ride, or whatever would get each other\’s adrenaline boiling.
I\’m sure you heard about the tips to increase chemistry with someone by touching your date on the knee or arm early on in the date. Obviously you want to be very careful with doing something like that. Getting physical early on may just end up turning your partner off. Instead of doing that, talk about what physical features you find most attractive in the opposite sex and then using the information you get with your date\’s reply to your advantage.
Relationships and chemistry ago hand-in-hand, although they are mysterious and can be hard to control. You may be able to get the upper hand by being yourself, having a sense of humor and enjoying your date\’s company. Everything else should fall into place if the relationship is meant to be taken farther.
By: Ted Denton
The first thing you have to know is what exactly is chemistry.
It can be pretty difficult to find chemistry if you\’ve never had it with a person, but if you have had it with someone you know exactly what chemistry is. The idea that pops into your head or floats into your unconscious is one that makes you feel that the two of you should be together no matter what. It is something that tells you that this feels just right… perhaps you two were meant to be together.
It can begin with the feeling that the two of you feel completely at ease with each other, and that you two have an uncanny physical attraction toward each other. While this attraction might be due to each other\’s looks, physical looks, in reality it comes down to a mental game. Game is probably the wrong word to use… Let\’s just say it could be a condition of your mental state. It could come down to something as simple as each having the same pet peeves, each knowing what the other is going to say before they say it and so on. Having the same beliefs, even the same dreams of what the future will hold for you can be the start of the chemistry you\’re looking for.
To be honest, before creating chemistry with someone you need to spend time with them and create a relationship of some type with this person. Needless to say this goes beyond the first, second, or even third date and have once you have spent more time together.
Look for a good topic or even something that you both enjoy doing to give you good conversation to start with. Good conversation is the key…if you don\’t have it, chances are you won\’t get that chemistry simmering and moving up to a boil. Don\’t start with politics or religion…yes…it\’s just like our parents taught us not to speak of these issues outside the circle of good friends. Save those topics until you become better acquainted. You don\’t need a high-stress point when you just are getting started. Start with a topic or subject you both can have fun with.
One big thing - if you have a great sense of humor - use it! And, hope the other person has one also. Laughter can break down many walls and help people to bond much more easily. And..keep the humor clean and not obscene, and without prejudice. I guess that\’s pretty obvious.
One other thing that is obvious: act like yourself. Don\’t try to be someone you\’re not. To have true chemistry with someone they have to know the real you. Don\’t keep all your opinions to yourself. Make it a point to share some of your thoughts and feelings about important issues…these issues may be also be important your partner. It\’s all up to the way you converse with the person as to whether that elusive chemistry can begin simmering.
Try to plan exciting dates, studies have shown that couples who meet in exciting situations tend to find each other more attractive. This pattern works because the mind associates any excitement with the person we are with at the time and mistakes it for physical attraction. You can make use of this feeling by planning a date that will get the adrenaline pumping… a scary movie, take a roller coaster ride, or whatever would get each other\’s adrenaline boiling.
I\’m sure you heard about the tips to increase chemistry with someone by touching your date on the knee or arm early on in the date. Obviously you want to be very careful with doing something like that. Getting physical early on may just end up turning your partner off. Instead of doing that, talk about what physical features you find most attractive in the opposite sex and then using the information you get with your date\’s reply to your advantage.
Relationships and chemistry ago hand-in-hand, although they are mysterious and can be hard to control. You may be able to get the upper hand by being yourself, having a sense of humor and enjoying your date\’s company. Everything else should fall into place if the relationship is meant to be taken farther.
By: Ted Denton
Aug
11
How does enantiomorphosis come to mean (via Canneti) prohibitions on becoming in Deleuze and Guattari?
Filed Under Physical Chemistry | 1 Comment
If an enantiomorph in crystallography / physical chemistry indicates a mirror image kind of symmetry between two crystals, then how do DG (via Canneti) recast enantiomorphosis as a death-dealing operation?
OK… so a crystal is formed in the image of another (only in reverse of the original). This formation somehow prohibits the matter of the formed crystal from becoming something else / taking a different form? Is that it?
By: nomadologist
OK… so a crystal is formed in the image of another (only in reverse of the original). This formation somehow prohibits the matter of the formed crystal from becoming something else / taking a different form? Is that it?
By: nomadologist
Aug
11
HSC Physics
Filed Under Physical Chemistry | Leave a Comment
Why choose HSC Physics
HSC Physics can be one of the most rewarding HSC subjects that is widely and commonly available across schools in NSW. HSC Physics tends to appeal to students with an interest for quantitative subjects like mathematics. In fact, if one is to try to define physics, it would be applied 2 unit maths. The mathematics in physics is certainly not difficult, but the problems in Physics are structured in terms of real-world applications. Therefore students who have a keen interest in the physical world and the theory behind its behavior are advised to take physics.
In terms of scaling, HSC physics has always scaled quite decently. Traditionally and in recent years, physics has had a scaled mean of about 29/50, meaning it scales slightly under HSC Chemistry, English Advanced and Economics. However physics has always scaled significantly better than biology, which is convenient since HSC Physics and Chemistry has always had a synergy about them. They are to a large extent similar courses, both requiring a similar skillset from students who want to do well. However, unlike HSC Chemistry, Physics is less experience-based, as there are less things upon which we need to refer to repeatedly throughout the course. ( For example, in Chemistry, we had to know the common valencies, solubility rules, how to name carbon compounds etc)
Instead, Physics requires more of an ability to imagine things yourself and conduct what we call ‘thought experiments’ in your own mind in order to understand the concepts taught in the course. This is more of a skill rather than a set of knowledge. For example, to gain a solid grasp of Einstein’s theory of special relativity and the associated equations, it is all about your ability to get your head around how time dilation operates in different frames, and in relation to each other. While theory helps and rote-learning the method of applying the equations, this approach is limited in its usefulness since slightly tricky exam questions can easily throw you off.
How to master HSC Physics
To get better at HSC Physics, since many things are very abstract and conceptual (e.g. to understand how an induction motor actually works, or Einstein’s equations of time and mass dilation, or the cause of striation patterns in vacuum tubes), it is a good idea to ask a teacher or tutor as many questions as possible. That means whenever there is some concept that you don’t understand, or even a tiny point within a wider concept, don’t leave it alone. You should ask all questions until you have a concrete understanding of the concept in question before moving on.
A good way is to constantly test your own knowledge by connecting all the related concepts together and seeing if there are any contradictions that a revealed by connecting up what you know. This is because physics is very conceptual in nature, and slightly different to the other sciences (Chemistry and Biology). Physics revolves around understanding abstract concepts, most of which can not be experimentally tested within a school lab, and some concepts can never be properly experimentally tested (e.g. whether the luminiferous aether really exists).
Successful physics students have a great ability to conduct thought experiments. What this involves is essentially testing out an idea in your mind, following physical rules you have learnt, to see whether you arrive at a conclusion that is absurd, or plausible. It’s difficult to truly understand this technique and to what extent we use it when thinking about concepts in Physics, but it is a good habit to always do this in order to verify and test your own understanding.
Good students would also have the ability to unify their understanding of various seemingly unrelated topics. One thing unique about HSC physics as opposed to other HSC sciences is that its topics are all latently linked, and based on a common set of fundamental physical principles. What we mean by ‘latent’ is that these links are not immediately visible, and the ability to draw these links is what separates a student who gets 95+ in their HSC mark, versus a student who doesn’t. For example, the same set of rules apply to forces on a cathode ray as those that are responsible for the motor effect. And it is the same principle (electromagnetic induction) which explains why magnetars (if you do Astrophysics) have such intense magnetic fields. This is the same line of thought that led Sir Isaac Newton to conclude that it is the force of gravity which keeps the Moon in a circular or bit around the Earth.
Different ways of thinking about one concept
For example, think of an induction motor: we are all taught by teachers that such a motor works because the squirrel cage ‘chases’ the spinning magnetic field, citing Lenz’s law. However what if you totally ignore your knowledge about Lenz’s law, can you try to explain how an induction motor works solely by using the right-hand push rule? Well actually you can, because as the magnetic field sweeps past a part of the squirrel cage, that’s like having a current move towards the opposite direction, which imparts a force along the cage onto the positive charge carriers as per the direction of your palm. This dictates the induced current flow, and if you then shift your thumb to point towards this current, you’ll notice the palm now points towards the direction the magnetic field was moving towards. In effect, the cage actually does ‘chase’ the field, however as you can see, we can explain it in terms of first principles rather than rely on sweeping statements like ‘induction motors work because of Lenz’s law’.
Another practical example highlighting the same point is attempting to explain the concept of an event horizon in terms of escape velocity. Without going into too much detail, recall that there is a formula to find escape velocity from a body of mass, and that it is inversely proportional to r, the distance from the centre of that mass. For black holes, since mass is all focused within a singularity of infinite density, there comes a point where r is sufficiently small that escape velocity reaches, then exceeds c, the speed of light. At the point where r makes the escape velocity exactly equal to the speed of light, this defines the boundary of the event horizon, beyond which no information can escape. If we further decrease r (i.e. get closer to the black hole), by then the calculated escape velocity exceeds c, and from Einstein’s mass dilation equations, this could never physically be achieved. Therefore this is a more practical and unified way of thinking about the concept of black holes and why they have an event horizon.
As a student aiming for 95+ (HSC aligned mark) in HSC Physics, without a doubt, your depth of knowledge, and the extent of drawing connections between your conceptual understanding, will determine whether you will reach your goal of 95+. That is, your ability to unify your understanding of the various topics of physics will help you significantly when it comes to showing depth in your understanding in exam responses.
By: Amarendra
HSC Physics can be one of the most rewarding HSC subjects that is widely and commonly available across schools in NSW. HSC Physics tends to appeal to students with an interest for quantitative subjects like mathematics. In fact, if one is to try to define physics, it would be applied 2 unit maths. The mathematics in physics is certainly not difficult, but the problems in Physics are structured in terms of real-world applications. Therefore students who have a keen interest in the physical world and the theory behind its behavior are advised to take physics.
In terms of scaling, HSC physics has always scaled quite decently. Traditionally and in recent years, physics has had a scaled mean of about 29/50, meaning it scales slightly under HSC Chemistry, English Advanced and Economics. However physics has always scaled significantly better than biology, which is convenient since HSC Physics and Chemistry has always had a synergy about them. They are to a large extent similar courses, both requiring a similar skillset from students who want to do well. However, unlike HSC Chemistry, Physics is less experience-based, as there are less things upon which we need to refer to repeatedly throughout the course. ( For example, in Chemistry, we had to know the common valencies, solubility rules, how to name carbon compounds etc)
Instead, Physics requires more of an ability to imagine things yourself and conduct what we call ‘thought experiments’ in your own mind in order to understand the concepts taught in the course. This is more of a skill rather than a set of knowledge. For example, to gain a solid grasp of Einstein’s theory of special relativity and the associated equations, it is all about your ability to get your head around how time dilation operates in different frames, and in relation to each other. While theory helps and rote-learning the method of applying the equations, this approach is limited in its usefulness since slightly tricky exam questions can easily throw you off.
How to master HSC Physics
To get better at HSC Physics, since many things are very abstract and conceptual (e.g. to understand how an induction motor actually works, or Einstein’s equations of time and mass dilation, or the cause of striation patterns in vacuum tubes), it is a good idea to ask a teacher or tutor as many questions as possible. That means whenever there is some concept that you don’t understand, or even a tiny point within a wider concept, don’t leave it alone. You should ask all questions until you have a concrete understanding of the concept in question before moving on.
A good way is to constantly test your own knowledge by connecting all the related concepts together and seeing if there are any contradictions that a revealed by connecting up what you know. This is because physics is very conceptual in nature, and slightly different to the other sciences (Chemistry and Biology). Physics revolves around understanding abstract concepts, most of which can not be experimentally tested within a school lab, and some concepts can never be properly experimentally tested (e.g. whether the luminiferous aether really exists).
Successful physics students have a great ability to conduct thought experiments. What this involves is essentially testing out an idea in your mind, following physical rules you have learnt, to see whether you arrive at a conclusion that is absurd, or plausible. It’s difficult to truly understand this technique and to what extent we use it when thinking about concepts in Physics, but it is a good habit to always do this in order to verify and test your own understanding.
Good students would also have the ability to unify their understanding of various seemingly unrelated topics. One thing unique about HSC physics as opposed to other HSC sciences is that its topics are all latently linked, and based on a common set of fundamental physical principles. What we mean by ‘latent’ is that these links are not immediately visible, and the ability to draw these links is what separates a student who gets 95+ in their HSC mark, versus a student who doesn’t. For example, the same set of rules apply to forces on a cathode ray as those that are responsible for the motor effect. And it is the same principle (electromagnetic induction) which explains why magnetars (if you do Astrophysics) have such intense magnetic fields. This is the same line of thought that led Sir Isaac Newton to conclude that it is the force of gravity which keeps the Moon in a circular or bit around the Earth.
Different ways of thinking about one concept
For example, think of an induction motor: we are all taught by teachers that such a motor works because the squirrel cage ‘chases’ the spinning magnetic field, citing Lenz’s law. However what if you totally ignore your knowledge about Lenz’s law, can you try to explain how an induction motor works solely by using the right-hand push rule? Well actually you can, because as the magnetic field sweeps past a part of the squirrel cage, that’s like having a current move towards the opposite direction, which imparts a force along the cage onto the positive charge carriers as per the direction of your palm. This dictates the induced current flow, and if you then shift your thumb to point towards this current, you’ll notice the palm now points towards the direction the magnetic field was moving towards. In effect, the cage actually does ‘chase’ the field, however as you can see, we can explain it in terms of first principles rather than rely on sweeping statements like ‘induction motors work because of Lenz’s law’.
Another practical example highlighting the same point is attempting to explain the concept of an event horizon in terms of escape velocity. Without going into too much detail, recall that there is a formula to find escape velocity from a body of mass, and that it is inversely proportional to r, the distance from the centre of that mass. For black holes, since mass is all focused within a singularity of infinite density, there comes a point where r is sufficiently small that escape velocity reaches, then exceeds c, the speed of light. At the point where r makes the escape velocity exactly equal to the speed of light, this defines the boundary of the event horizon, beyond which no information can escape. If we further decrease r (i.e. get closer to the black hole), by then the calculated escape velocity exceeds c, and from Einstein’s mass dilation equations, this could never physically be achieved. Therefore this is a more practical and unified way of thinking about the concept of black holes and why they have an event horizon.
As a student aiming for 95+ (HSC aligned mark) in HSC Physics, without a doubt, your depth of knowledge, and the extent of drawing connections between your conceptual understanding, will determine whether you will reach your goal of 95+. That is, your ability to unify your understanding of the various topics of physics will help you significantly when it comes to showing depth in your understanding in exam responses.
By: Amarendra
Aug
9
Okay ladies, if you have a physical connection with a man, but he just doesn’t get you mentally, what next?
Filed Under Physical Chemistry | 7 Comments
I have a women friend that we have a STRONG physical attraction, chemistry (that’s what you ladies call it) towards each other, but I just can’t get her mentally at all. Each time we talk, the least bit, its painful, she gets upset, I’m pissed cause I’m confused, and it just sucks!!
What do you do next.
By: pluto
Aug
8
men-please be serious and answer all questions- my boyfriend told me he cared a lot but not enough chemistry?
Filed Under Physical Chemistry | 2 Comments
most important question- can you care a lot about someone you dont have enough chemisty with?
is chemistry physical attraction and sex? or is chemistry how well too people get along?
can you be physically attracted to a women or man , have awesome sex, but litttle chemistry?
can you have awemome chemistry but little physical attraction?
By: wishing
Aug
7
What are some physical properties of plastic that would be appropriate for making rain boots?
Filed Under Physical Chemistry | 2 Comments
chemistry help! Thanks!
By: Break Dance, Not Hearts!
By: Break Dance, Not Hearts!
Aug
2
Grey’s Anatomy: Episode 4.7 "physical Attraction. Chemical Reaction" Recap
Filed Under Physical Chemistry | Leave a Comment
The last episode of Grey’s Anatomy was all about sex, literally. We saw Izzie complaining about her chemistry with George, or the lack thereof. The same can’t be said about Derek and Meredith, though, as the two were brimming with sexual tension. However, Derek thought that their relationship lacked more of the love. Moreover, Mark teased Derek of being the Chief’s new girlfriend when Derek frequently picked up the Chief’s dry cleaning for him, and subsequently had dinner and a movie with him.
Meredith experienced some sister trouble when she forbid Lexie to sleep with Alex at Meredith’s place. Meredith even told her off, saying that Lexie should start living her own life and get her own friends. Not wanting to get in between them, Alex kept his distance.
Callie, on the other hand, went through a rough time dealing with her administrative responsibilities, and thus asked help from Bailey, who gladly covered for her while she scrubbed in for back-to-back duties.
Featured patients tonight were the marbles-swallowing kid whom George attended, a man who couldn’t move his bowels, who was attended by Alex, and an annoying woman demanding for a facelift, attended by Izzie. The bowel guy and facelift woman annoyed Izzie and Alex so much that they followed Bailey’s advice of placing them in the same room, so that they could annoy each other. However, their plan failed as the two became more than just friends in a matter of hours. The two patients hit it off so well that when Alex and Izzie walked in, they were having sex. This made Izzie realize how much she and George lacked chemistry, and made her resentful about it.
For the night, Cristina attended to a woman who fell down the stairs while carrying her adopted baby. Lexie was in charge of the baby, while Erica took over the mother, who later on died, leaving her husband to take care of the baby he named Keisha.
The end of the episode, Izzie and George finally develop some chemistry, causing them to have the best sex ever.
For more resources about Grey’s Anatomy or for the full story of Grey’s Anatomy: Episode 4.7 “Physical Attraction… Chemical Reaction” Recap please review http://www.buddytv.com
By: Groshan Fabiola
Meredith experienced some sister trouble when she forbid Lexie to sleep with Alex at Meredith’s place. Meredith even told her off, saying that Lexie should start living her own life and get her own friends. Not wanting to get in between them, Alex kept his distance.
Callie, on the other hand, went through a rough time dealing with her administrative responsibilities, and thus asked help from Bailey, who gladly covered for her while she scrubbed in for back-to-back duties.
Featured patients tonight were the marbles-swallowing kid whom George attended, a man who couldn’t move his bowels, who was attended by Alex, and an annoying woman demanding for a facelift, attended by Izzie. The bowel guy and facelift woman annoyed Izzie and Alex so much that they followed Bailey’s advice of placing them in the same room, so that they could annoy each other. However, their plan failed as the two became more than just friends in a matter of hours. The two patients hit it off so well that when Alex and Izzie walked in, they were having sex. This made Izzie realize how much she and George lacked chemistry, and made her resentful about it.
For the night, Cristina attended to a woman who fell down the stairs while carrying her adopted baby. Lexie was in charge of the baby, while Erica took over the mother, who later on died, leaving her husband to take care of the baby he named Keisha.
The end of the episode, Izzie and George finally develop some chemistry, causing them to have the best sex ever.
For more resources about Grey’s Anatomy or for the full story of Grey’s Anatomy: Episode 4.7 “Physical Attraction… Chemical Reaction” Recap please review http://www.buddytv.com
By: Groshan Fabiola
Aug
2
what determines the physical state of a substance at room tempurature?
Filed Under Physical Chemistry | 5 Comments
it is a chemistry hw assignment.
By: lotyr14
By: lotyr14
Aug
1
i want help with my chemistry project ! could u please tell me a suitable topic that i can choose n do well?
Filed Under Physical Chemistry | 7 Comments
i m class 12 science.i want a suitale topic according to my level .something nice of chemistry (physical experiment) if u know of a nice projecT please e mail me at alice_princes@yahoo.com ITS URGENT PLEASE HELP ME
By: princess
By: princess
Jul
30
Branch Of Chemistry Dealing With Study Of Reaction Rates
Filed Under Physical Chemistry | Leave a Comment
Chemical kinematics is the branch of chemistry that deals with the study of reaction rates or even speed of reaction and their mechanics. The kinetic studies not only help us to determine the reaction rates but also does describe the conditions by which the reaction rates can be altered. Besides this the mechanism governing the reactions could also be predicted on the basis of logical kinetic data.
During the course of study we all come across a wide variety of chemical reactions having different rates. In thermodynamics we studied that the decrease in free energy is quite helpful in predicting the feasibility of chemical reactions. However, knowledge of free energy change of reaction does not give us any idea about the speed or rate of the reaction.
So, depending upon the reaction rates, various reactions can be categorized into three types as very fast, very slow or moderately slow. Very fast reaction’s are those which occur almost instantaneously like precipitation of silver chloride which occur instantaneously by simply adding aqueous solution of sodium chloride to aqueous solution of silver nitrate. The rates of such reactions cannot be determined easily. The obvious reason for a very fast rate of such reaction is that no chemical bonds are to be broken among the reactants.
Very slow reactions comprises reactions which occur at a very slow rate. These reactions may require month or even years together for their completion like rusting of iron. The rates of such reactions are hardly of any physical importance. Moderately slow reactions refer to reactions in between very fast type and very slow type reactions. These reactions proceed at moderate speed which can be easily measured. Inversion of cane sugar and hydrolysis of starch are common examples of this type of reactions.
The rate of a chemical reaction can also be determined as the speed or velocity with which a reaction takes place. It can be expressed qualitatively as well as quantitatively. The qualitative rate is based on certain visual parameters like disappearance of reactants, color change, effervescence, etc. the rate expressed as such provides arbitrary conclusions about the rate of a reaction. Quantitative rate of a chemical reaction provides with much better information about the rate data and the accurate rate of a reaction. Quantitatively, the rate of chemical reaction may be expressed as the rate of decrease in concentration of any one of the reactants or the rate of increase in concentration of any one of the products. Thus the reactions may be involving same stoichiometric coefficients of all the reactants and products like in the case of reaction between nitrogen dioxide and carbon monoxide, as the reactants and products appear in the same stoichiometric proportions. So the rate of the reaction may be expressed in terms of rate of disappearance of nitrogen dioxide or carbon monoxide or alternatively, by the rate of appearance of carbon dioxide or nitric oxide which ever may be convenient. In this case the rate of reaction can be followed easily by simply measuring the change in intensity of color.
If the reactants and products have different stoichiometric coefficients, this means that for every mole of the reactants reacting we get two moles of the products. So the rate of formation of the products will be twice the rate of disappearance of the reactants. So, in order to avoid the difference in the two rates, i.e., to get a unique value of the reaction rate irrespective of the species selected, we simply divide the rate of change of concentration by the stoichiometric coefficient of reactant or product that are involved in the chemical reaction.
By: lalit sharma
During the course of study we all come across a wide variety of chemical reactions having different rates. In thermodynamics we studied that the decrease in free energy is quite helpful in predicting the feasibility of chemical reactions. However, knowledge of free energy change of reaction does not give us any idea about the speed or rate of the reaction.
So, depending upon the reaction rates, various reactions can be categorized into three types as very fast, very slow or moderately slow. Very fast reaction’s are those which occur almost instantaneously like precipitation of silver chloride which occur instantaneously by simply adding aqueous solution of sodium chloride to aqueous solution of silver nitrate. The rates of such reactions cannot be determined easily. The obvious reason for a very fast rate of such reaction is that no chemical bonds are to be broken among the reactants.
Very slow reactions comprises reactions which occur at a very slow rate. These reactions may require month or even years together for their completion like rusting of iron. The rates of such reactions are hardly of any physical importance. Moderately slow reactions refer to reactions in between very fast type and very slow type reactions. These reactions proceed at moderate speed which can be easily measured. Inversion of cane sugar and hydrolysis of starch are common examples of this type of reactions.
The rate of a chemical reaction can also be determined as the speed or velocity with which a reaction takes place. It can be expressed qualitatively as well as quantitatively. The qualitative rate is based on certain visual parameters like disappearance of reactants, color change, effervescence, etc. the rate expressed as such provides arbitrary conclusions about the rate of a reaction. Quantitative rate of a chemical reaction provides with much better information about the rate data and the accurate rate of a reaction. Quantitatively, the rate of chemical reaction may be expressed as the rate of decrease in concentration of any one of the reactants or the rate of increase in concentration of any one of the products. Thus the reactions may be involving same stoichiometric coefficients of all the reactants and products like in the case of reaction between nitrogen dioxide and carbon monoxide, as the reactants and products appear in the same stoichiometric proportions. So the rate of the reaction may be expressed in terms of rate of disappearance of nitrogen dioxide or carbon monoxide or alternatively, by the rate of appearance of carbon dioxide or nitric oxide which ever may be convenient. In this case the rate of reaction can be followed easily by simply measuring the change in intensity of color.
If the reactants and products have different stoichiometric coefficients, this means that for every mole of the reactants reacting we get two moles of the products. So the rate of formation of the products will be twice the rate of disappearance of the reactants. So, in order to avoid the difference in the two rates, i.e., to get a unique value of the reaction rate irrespective of the species selected, we simply divide the rate of change of concentration by the stoichiometric coefficient of reactant or product that are involved in the chemical reaction.
By: lalit sharma