Partial molar property

Partial molar property INTRODUCTION A partial molar property is the contribution (per mole) that a substance makes to an overall property of a mixture. The easiest partial molar property to visualize is the partial molar volume, vj of a substance j the contribution j makes to the total volume of a mixture. we can see that although 1 mol of a substance has a characteristics volume when it is pure,1 mol of that substance can make different contributions to the total volume of a mixture because molecules pack together in different ways in the pure substance and in mixture. the partial molar volume at an intermediate composition of the watterethanol mixture is an indication of the volume the H2o molecules occupy when they are surrounded by a mixture of molecules representative of the overall composition(half water, half ethanol) for instance. when the molar fraction are both 0s. The partial molar volume, VJ, of any substance J at a general composition, is defined as: where the subscript n indicates that the amount of all the other substances is held constant. The partial molar is the slope of the plot of the total volume as the amount of J is changed with all other variables held constant: it is quite possible for the partial molar volume to be negative, as it would be at II in the above diagram. For example, the partial molar volume of magnesium sulphate in water is -1.4cm3 mol-1. i.e. addition of 1 mol MgSO4 to a large volume of water results in a decrease in volume of 1.4 cm3. (The contraction occurs because the salt breaks up the open structure of water as the ions become hydrated.) Once the partial molar volumes of the two components of a mixture at the composition and temperature of interest are known, the total volume of the mixture can be calculated from: The expression may be extended in an analogous fashion to mixtures with any number of components. The most common method of measuring partial molar volumes is to measure the dependence of the volume of a solution upon its composition. The observed volume can then be fitted to a function of the composition (usually using a computer), and the slope of this function can be determined at any composition of interest by differentiation. PARTIAL MOLAR GIBBS ENERGY The most useful partial molar quantity is the partial molar free energy Gi,pm. It is so useful that it is given the name of chemical potential and a separate sumbol  µi . the chemical potential is just another name for the molar Gibbs energy. For a substance in a mixture, the chemical potential is defined as being the partial molar Gibbs energy: i.e. the chemical potential is the slope of a plot of the Gibbs energy of the mixture against the amount of component J, with all other variables held constant: In the above plot, the partial molar Gibbs energy is greater at I than at II. The total Gibbs energy of a binary mixture is given by: where the sum is across all the different substances present in the mixture, and the chemical potentials are those at the composition of the mixture. This indicates that the chemical potential of a substance in a mixture is the contribution that substance makes to the total Gibbs energy of the mixture. In general, the Gibbs energy depends upon the composition, pressure and temperature. Thus G may change when any of these variables alter, so for a system that has components A, B, etc, it is possible to rewrite the equation dG = Vdp SdT (which is a general result that was derived here) as follows: The idea that the changing composition of a system can do work should be familiar this is what happens in an electrochemical cell, where the two halves of the chemical reaction are separated in space (at the two electrodes) and the changing composition results in the motion of electrons through a circuit, which can be used to do electrical work. it is possible to use the relationships between G and H, and G and U, to generate the following relations: Now H=U+PV To measure partial molar volumes There are several ways that partial molar volumes can be measured. One way is to begin with one mole of a compound, call it component 1, add a small amount of component 2 and measure the volume, add a little more of component 2 and measure the volume again. Keep doing this until the desired concentration range has been covered. Then fit the volume data to a curve, for example, of the form, The constants, a, b, c, etc are obtained from the curve fitting and the first term is the molar volume of pure component 1. Then the partial molar volume of component 2 can be obtained by direct differentiation, Ideal Solutions We will define an ideal solution as a solution for which the chemical potential of each component is given by, whereis the chemical potential of pure component i, and Xi is the mole fraction of component i in the solution. whereis the vapor pressure of pure component i.) We have to prove that an ideal solution obeys Raoults law (using definition). Consider a solution of two components where the mole fraction of component 1 is X1. We know that the chemical potential of component 1 must be the same in the solution as in the vapor in equilibrium with the solution. That is, Equation 10 doesnt help us very much all by itself. However we have some more information. We know that for the pure component 1 we have X1 = 1, and we know that the pressure of component 1 vapor in equilibrium with the liquid is just the vapor pressure of the pure liquid, p1*, so that, which is Raoults law. [5]Chemical potential of an ideal gas the chemical potential  µ of an ideal gas at a given temperature is related to its pressure p through eq.  µ= µ + RT ln(p/p0) (15) where  µo is the standard chemical potential when the when the pressure of the gas is po, equation 15 suggest that at a given temperature, the pressure of the gas is a measure of its chemical potential. if inequalities in pressure exist in a gas container, the gas flows spontaneously from the high pressure region to the lower pressure region until the pressure is equalized throughout the vessel. In the later stage, the gas has the same value of chemical potential throughout the container. IMPORTANCE OF CHEMICAL POTENTIAL The chemical potentials are the key properties in chemical thermodynamics. the  µi determine reaction equilibrium and phase equilibrium. Moreover, all other partial molar properties and all thermodynamics properties of the solution can be found from the  µi ‘s APPLICATIONS Partial molar properties are useful because chemical mixtures are often maintained at constant temperature and pressure and under these conditions, the value of any extensive property can be obtained from its partial molar property. They are especially useful when considering specific properties of pure substances (that is, properties of one mole of pure substance) and properties of mixing. Δmix H ≠¡ H H*, Δ mixS≠¡ S S*, ΔmixG≠¡G G* Where H,S and G are properties of the solutions and H*,S*, And G* are properties of the pure unmixed components at the same T and P as the solution. the key mixing quantity is ΔmixG =G G*. The Gibbs energy G of the solution is G=iGi(where Gi is a partial molar quantity). The gibbs energy G* of the unmixed components is G*=iG*m,i(where G*m,i is the molar Gibbs energy of pure substance i). Therefore ΔmixG≠¡ G G* = i(Gi G*m,i) const T,P (1) which is similar for ΔmixV. we have ΔmixG = ΔmixH TΔmixS const T,P (2) which is a special case of ΔG =ΔH TΔS at constant T. ΔmixS and ΔmixV can be found as partial derivatives of ΔmixG. Taking (T,nj of eq(1), we have = i G*m,i) = i T,nj = i(Vi V*m,i) T,nj =ΔmixV (3) The changes ΔmixV, ΔmixU, ΔmixH, ΔmixCp that accompany solution formation are due entirely to changes in intermolecular interactions( both energetic and structural). However, changes in S,A and G result not only from changes in intermolecular interactions but also from the unavoidable increase in entropy that accompanies the constant T and P mixing of substance and the simultaneous increase in volume each component occupies. Even if the intermolecular interactions in the solution are the same as in the pure substances, ΔmixS and ΔmixG will still be no zero. GIBBS- DUHEM EQUATION A relation that imposes a condition on the composition variation of the set of chemical potentials of a system of two or more components, where Sis entropy, Tabsolute temperature ,Ppressure, nithe number of moles of the ith component, and ÃŽ ¼iis the chemical potential of the ith component. Also known as Duhems equation. Deriving the Gibbs-Duhem equation for volume. The total differential of the Gibbs free energy in terms of its natural variables is With the substitution of two of the Maxwell relations and the definition of chemical potential, this is transformed into: the chemical potential is just another name for the partial molar (or just partial, depending on the units of N) Gibbs free energy, thus The total differential of this expression is Subtracting the two expressions for the total differential of the Gibbs free energy gives the Gibbs-Duhem relation: FUGACITY The presences of molecular interactions distinguish the real gases from ideal gases where the molecular interactions are completely absent. For a real gas Vm ≠  RT/P and hence d µÃ¢â€°  RT d ln P. Since the ideal gas equations are not directly applicable to real gases, we are faced with a problem. We can either sacrifice the equations or the variable. If we abandon the general equation of chemical potential then we have to use various equation of state fitting with P-V-T data. The use of such equations of state will make the treatment more complicated. So we find it easier to retain the general form of the chemical potential and to define a new variable which has the dimensions and general properties of pressure. The new variable is called the fugacity, which is derived from the Latin fugere, to flee, and means literally ‘escaping tendency. It is denoted by f. it is a corrected pressure which applies to real gases. all the effects arising due to interactions are containe d in f. the chemical potential of a pure real gas can be expressed in a form  µ= µo + RT ln(f/atm)  µo is the standard chemical potential at unit fugacity. at very low pressure . the ratio (f/p) = ÃŽ ³ is called the fugacity coefficient. for an ideal gas f=p and the fugacity coefficient is unity. with this definition of the fugacity we may now express the chemical potential as:  µ= µo + RT ln(ÃŽ ³P/atm) =  µo + RT ln(P/atm) + RT ln ÃŽ ³ on compairing this expression with that for an ideal gas[ µideal =  µo + RT ln(P/atm) Condition of fugacity of a gas Let us consider the relation d µ= VmdP d µ = Vm(ideal)dP and d µ(real) = Vm(real) dP Let us consider a change in the state of the system from an initial pressure P ´ to a final pressure P, and let f ´ be the fugacity of the real gas at pressure P ´ and f the fugacity at pressure P. Integration of the expression for chemical potential yields (ideal) = m(ideal)dP or  µ(ideal)  µÃ‚ ´(ideal) = m(ideal)dP and  µ(real)  µÃ‚ ´(real) = m(real)dP but for an ideal gas the chemical potential is given by  µ(ideal) =  µo(ideal) + RT ln(P/atm)  µÃ‚ ´(ideal) =  µo(ideal) + RT ln(P ´/atm)  µo is the standard chemical potential.  µ(ideal)-  µÃ‚ ´(ideal) = RT ln(P/P ´) = m(ideal)dP (1) For the real gas  µ(real) =  µo(real) + RT ln(f/atm) and  µÃ‚ ´(real) =  µo(real) + RTln(f/atm)  µ(real)  µÃ‚ ´(real) = RT ln(f/atm) RT ln(f ´/atm) = RT ln(f/f ´) = m(ideal)dP (2) Taking the difference of equation (2) and (1), we get RT ln(f/f ´) RT ln(P/P ´) = m(real) Vm(ideal)]dP or RT ln(f/P) RT ln(f ´/P ´) = m(real) Vm(ideal)]dP (3) where = Vm(ideal) Vm(real) now, = + RT ln(f/p) RT ln(f ´/P ´) = + (4) If the pressure P ´ is very low then the gas will behave ideally and for this condition Vm(ideal) ≈ Vm(real) and = 1, The second term or left side and right side of equation (4) will be equated to zero, therefore RT ln(f/P) = or ln(f/P) = -1/RT Antilograthim gives (f/P) = exp or f= P exp( = P exp[Vm(real) Vm(ideal) )]dP (5) SUMMARY we had covered in this term paper about partial molar properties one important thing is The properties of a solution are not additive properties, it means volume of solution is not the sum of pure components volume. When a substance becomes a part of a solution it looses its identity but it still contributes to the property of the solution. The term partial molar property is used to designate the component property when it is a mixture with one or more component solution. the most important partial molar quantity is the partial molar free energy it is an intensive property because it is a molar quantity.it is denoted by  µi.now we also know that how to measure the partial volume. and then the ideal solution is the solution in which the components in pure form here we take the pure components of chemical potential . then the applications of partial molar property is the property of mixing which is very useful. it is defined in term paper and the important concept Gibbs duhem equation A relation that imposes a condition on the composition variation of the set of chemical potentials of a system of two or more components physical significance is that if the composition varies,the chemical potentials do not change independently but in a related way.and then included fugacity another important part of partial molar properties. The fugacity f plays the role of pressure and need not be equal to the actual pressure of the real gas. RESULT The overall result is the partial molar property is not of all about pure components. The term partial molar property is used to designate the component property when it is a mixture with one or more component solution. and also find out the chemical potential other name of gibbs energy and about ideal gases, fugacity.

Its Time to Legalize Drugs Essay -- Drug Legalization

No one can honestly claim that current American drug policies have been a success. To the contrary, the current policy of drug prohibition, aside from being ineffective and costly, has created a set of unwanted consequences including: a high prison population of non-violent offenders, corruption within law enforcement, health issues, and an erosion of civil liberties . Albert Einstein said, â€Å"Insanity is doing the same thing over and over and expecting different results.† Yet despite the failures of the current policy in deterring drug use that is just what the government is choosing to do. It’s time to consider a different approach to the drug issue. An approach that will address drug use in an innovative way while solving the problems which drug prohibition has created while also bringing societal, health, and economic benefits but most importantly it will also give back the individual liberties. It’s time to consider the legalization of drugs. Drug prohibition has proven to be a very costly war. Currently the government spends $47.8 billion a year on prohibition enforcement, according to a 2010 Department of Economics, Harvard University report by Jeffrey A. Miron. Yet despite the exorbitant amount of money being spent fighting this â€Å"war on drugs†, drugs are still prevalent on our streets. A 2008 a report found the US leads the world in illegal drug use with a whopping 42.4% of Americans admitting to trying illegal drugs at least once. (Warner) In 2009 a the Federal Substance Abuse and Mental Health Services Administration found that nearly 21.8 million Americans (equivalent to about 8.7% of the population) used illegal drugs had used drugs within the last year. (Hananel) Furthermore according to the White House Drug... ... York Times. 24 Mar. 2009. Web. 27 Nov. 2010. . Sterling, Eric E. "Foreign Policy In Focus | Drug Policy: Failure at Home." Foreign Policy In Focus | Home. 6 Oct. 2005. Web. 28 Nov. 2010. . United States. General Accounting Office. General Government Division. LAW ENFORCEMENT Information on Drug-Related Police Corruption. May 1998. Web. 28 Nov. 2010. Warner, Jennifer. "U.S. Leads The World In Illegal Drug Use - CBS News." Breaking News Headlines: Business, Entertainment & World News - CBS News. 1 July 2008. Web. 28 Nov. 2010. . Wisotsky, Steven. "A Society of Suspects: The War on Drugs and Civil Liberties." USA Today [Farmingdale] July 1993: 17-21. SIRS Researcher. Web. 23 Nov. 2010.

Criteria for Example Essay

The Criteria For A Good Example Essay There are several factors that contribute to good example essay writing. Having excellent grammar, using words correctly, punctuation, and presentation are the biggest points to me. Grammar is important for several reasons. Grammar is what enables us to make structured sentences. Everyone uses grammar to form a sentence. If you have bad grammar, the point of your sentence(s) may become unclear and make it hard for a reader to understand what you are saying. Using words correctly shows that you have a basic knowledge and understanding of grammar. It is a pet-peeve of mine. If someone writes, â€Å"There enrolled in English class. † as opposed to, â€Å"They're enrolled in English class. † it makes them sound less educated then someone who uses the right form of the word. Using punctuation the right way is very important because it can change the whole meaning of a word or the structure of your sentence. For example: if someone is trying to say, â€Å"There is the classroom for my English class. and they write, â€Å"They're is the classroom for my English class. † it changes the sentence to â€Å"They are is the classroom for my English class. † It just simply doesn't make sense. Also, punctuation allows a writer to separate thoughts, show where someone speaking would normally pause, and make the sentence more easily understood to the reader. Presentation is, in my opinion, the most important thing. It remind s me of my career with food, for example. There could be the most amazing tasting dish in front of you but you would never know it if the plate was a sloppy mess. You are more likely to enjoy a dish if it appears to look appealing before you've even tasted it. The same goes with an essay. If the format is all wrong and it is hard to understand, you will be more likely to think the content isn't well prepared and thought out. In conclusion, I believe you can create your own idea of the criteria for good essay writing. This was my example of what I think it takes to be a successful essay writer. You must have a strong knowledge of all the components you believe are important to successfully express your statement.

IPT essays

IPT essays Mister says: nuttin dyu no of nethin on 2nite? If you are not already familiar with this vague, unstructured dribble than the only plausible explanation is that you must be an over 60 year old woman living alone with her poodle, because to the rest of the world this is the new way of communicating. The emotionless and insensitive computer language adopted by every computer owner on the planet is progressing towards means of expression that is devoid of the emotive and necessary intimacy so definitive of humans interaction. Historically, interaction between humans has been the basis to a social life. It individually defines each person through the way it is deployed in the forms of language, expression and body movement. Programs like MSN messenger and Microsoft Net meeting intrude on this personal experience and even describe their services as a way to Flirt, banter, gossip, or just catch up without saying a word. The idea that you could have an intimate chat with someone over a machine seems somewhat impossible however people have been brainwashed into believing it to be the most convenient and efficient way. The use of all this technology with no real relation to human interaction can lead to a secluded and detached way of life. A good example of this is the characters personalities, or lack of, in the movie The Matrix. All the characters are intensely involved in the computer programming world and nothing else seems to pass through their train of thoughts. Although there is a supposed great love between Neo and Trinity do we ever really see this expression of passion and desire other than their sexual interaction which even then lacks the true connection of emotion. They have been programmed into seeing life as a task that must be completed and already it seems that humanity as fallen into the trap of believing that our reason on being is to advance humanity and all ...

Master Management and Change Essay

Master Management and Change Essay Master: Management and Change Essay Creating Sustainable Change: A new paradigm in Project Management Ron Schipper Senior Consultant, Van Aetsveld Project and Change management, Amersfoort, the Netherlands Harry Rorije Principal Consultant, Van Aetsveld Project and Change management, Amersfoort, the Netherlands Gilbert Silvius 1 Professor of Business, ICT and Innovation, University of Applied Sciences, Utrecht, the Netherlands Principal Consultant, Van Aetsveld Project and Change management, Amersfoort, the Netherlands Abstract Projects can be seen as a system to realize change in organizations. This change can involve new work processes, new policies, new resources, new products or services, etc. Sustainable change in these policies, processes, products, etc, requires different behavior of the workers or employees of the organization. It is, however, this aspect of change that most projects seem to oversee. In this paper, we will argue that changing or influencing the behavior of an organization’s employees is a crucial element in realizing change. The contemporary insights in human behavior and behavioral change, however, seem to contradict the more mechanical approach to projects that most project management methodologies prescribe. Controlling behavioral change, if possible, may require a different paradigm to projects and organizational change. Our paper will shed some light on this contradictory topic and will provide practical suggestions for the integration of behavioral change aspec ts in project management. Keywords Project management, Sustainable Change, Management of Change Introduction Projects can be considered as temporary organizations (Turner and Mà ¼ller, 2003) that deliver (any kind of) change to organizations, products, services, policies or assets (Gareis, 2010). Successful change most often requires a change of human behavior and therefore is influenced by the motivation to overcome resistance to change (Kotter, 1996). Gareis (2010), however, concludes that this kind of change is not adequately recognized in project management and that â€Å"specific change methods are to be applied according to the specific change requirements†. This paper provides an overview and practical suggestions for the integration of behavioral change aspects in both portfolio and project management. The question asked is how to realize sustainable behavioral change (when that is intended with the project)? Many publications (e.g. Boonstra, 2004; Cummings and Worley, 1996) show a managerial perspective on change: behavioral change is something that can be plan ned and managed top-down. However, this perspective is increasingly being questioned. People are free individuals who decide for themselves to show certain behavior. All attempts made in the past to force members of the organization to behave differently and the rewarding or punishing act on it has never led to sustainable behavioral change. It led to short-term changes with fall-back (Anderson, 2002; Beer 1990; Homan, 2005). This perspective creates this paper’s main question: which circumstances need to be created by project in order to make sustainable behavioral change occur? In this paper we focus on how the ‘forgotten group’ in organizations, the employees, experience change in projects. In the next paragraph will elaborate on what is meant with this ‘forgotten group’. We will then look at change from the perspective of this group. How do employees experience changes? How do they handle changes? When are they effected by change? When do they ch ange their behavior permanently? By practicing this perspective we will gained interesting insights, for example that managing for shorter lead times for projects actually hinders sustainable behavioral change. The paper will be concluded with some recommendations on how to connect with employees and integrate behavioral change into projects and project portfolios. 1 Corresponding author: Utrecht University of Applied Sciences, Padualaan 101, 3584 CH Utrecht,

Chinese Nationalists and Chinese Communists in China in the 1920s Essay

Chinese Nationalists and Chinese Communists in China in the 1920s - Essay Example In his article, Analysis of the Classes in Chinese Society, Mao Tse-tung argues that the lower classes of Chinese society will provide the main support for the communist revolution because they have low economic status and are victims of the capitalist exploitation of international imperialism. According to Mao, the origin of massive class disparity in China is the imperial capitalism which places most of the national resources in the hands of a small elite group and leaves the majority of the population, which comprises of peasants and low-level workers, economically deprived and struggling excessively in their efforts to earn a living. Mao believes that these struggling classes are the real friends of the revolution because they stand to benefit tremendously in a system whereby national resources are equitably distributed to all citizens (Tse-tung, Marxists.org).Thesis: Mao’s argument on economic disparity between classes in Chinese society illustrates the reason for the con stant conflict between the Chinese Nationalists and Chinese Communists in the 1920s. Mao’s argument plays a significant role when considering the differences between the Chinese Nationalists and Chinese Communists in China in the 1920s. The policies of the Nationalists tended to lean towards western ideals of capitalism and international imperialism. These policies favored the high classes of Chinese society at the expense of the lower classes. The high classes benefited from this system because they owned capital which they could use for productive purposes. They kept the proceeds from these productive purposes all to themselves, paying peasant workers small wages and overworking them. On the other hand, the Communists recognized that resources are limited, and not everyone in the society can acquire significant resources that will enable them to live comfortably. Therefore, they believed that the government should have sole control of all resources and distribute them equal ly to all members of the society (Ebrey, Walthall and Palais, 427). These massive ideological differences pitted the Communists against the Nationalists in the struggle to establish control over the divided country. It quickly became apparent to the Communists that they would have to drive the Nationalists from power for them to be able to spread the ideals of the revolution. Regime change and complete overhaul of the old system would have to take place if the communist revolution were to achieve success. Consequently, the Communists were a direct threat to the survival of the Nationalist government and to its grip on power and influence. As a result, the Nationalists realized that they would have to stem communist ideals from spreading throughout China in order to prevent the Communists from acquiring enough support to mount a revolution (Ebrey, Walthall and Palais, 431). Throughout the 1920s, there was conflict between the Nationalists and the Communists. The Communists were attem pting to grow their movement whereas the Nationalists were bent on preventing from them from gaining a foothold among rural Chinese peasants and urban dwellers. For example, the Communist Party gained a massive following among members of the General Labor Union of Shanghai. This following enabled the Communist Party to influence the GLU to call for a general strike on March 1921. Consequently over six hundred thousand workers seized the city and demanded a return of foreign concessions. Soldiers and members of the Green Gang loyal to Chiang Kaishek of the Nationalist Party immediately mounted a response, shooting and killing an estimated 5,000 union members and also attacked the union headquarters. This terror did not end with Shanghai. It quickly spread to other Chinese cities whereby soldiers of the Nationalist government destroyed bases of the Communist Party (Ebrey, Walthall and Palais, 427). These events demonstrated the fear that the Nationalists had over the Communists gainin g

Women and Publishing in Early America Essay Example | Topics and Well Written Essays - 750 words

Women and Publishing in Early America - Essay Example It is therefore pleasantly surprised to discover that as far back as 1476, women have made lifelong occupations in journalism and printing, and in various capacities including that of the owner. Mayo (2009) names at least 21 women who ran their husbands’ or fathers’ printing businesses after they died. Among them was Clementina Rind, who took over as publisher of the Virginia Gazette after she was widowed. Women of different races and classes contributed to the printing trade. For instance, Phillis Wheatley was a black poet and slave who wrote Poems on Various Subjects, Religious and Moral in the year 1773 (Duboi & Dumenil, 2005, in Mayo, 2009). Born in Africa (most likely Senegal), she was kidnapped at the age of eight years and brought to Boston. The white family which brought her gave her their family name as was the custom then, and she was taught English and Christianity, and later on ancient history, mythology and classical literature. She was intelligent, and her masters were a family of culture, so she was allowed to study and write. Her first poem was published in 1767 in the Newport Mercury. A collection of her poems was published in 1773 in London, and what was unusual was the â€Å"attestation† by seventeen men in the volume’s preface that, indeed, the poems were written â€Å"by Phillis, a young Negro Girl†¦a Barbarian from Africa†¦a Slave in a Fam ily† who was â€Å"examined by the best Judges, and is thought qualified to write them† (Lewis, 2007). Phillis Wheatley is acknowledged to be the first black woman poet in American history. The â€Å"attestation† is a clear bias against women, people of color, and of the lower classes (i.e., slaves). The need for such attestation by sixteen men, and the requisite to be examined by â€Å"the best Judges† provides a picture of how women who were in the literary and printing trades were regarded; the obvious presumption about women in their day-to-day life is that they are normally not capable of producing literary and journalistic pieces, and such works by women should be properly certified by white men.