Volumetric Analysis to Find Concentration of Acid

Volumetric Analysis to Find Concentration of Acid A. Dilshan Jayawickrama Introduction: Volumetric Analysis is a quantitative method and which deals with the volume of a particular substance used in the analysis. However in volumetric analysis most important factor is the volume. Here the volumetric analysis is proceed with known amount of solutions. But, concentrations of both the solution has not been mentioned since it is done to find out the concentration of known acid or a base. When adding known concentration solution to unknown concentration solution drop wise will result a color change at a point and this procedure called Titration. In volumetric analysis there are 5 main types as acid base titration, redox titration, precipitation titration, complexometric titration and iodometric titration (Datta and Johar, 2014). Titration is the process of observing the color change of mixed solution when known concentration solution is added to unknown concentration solution. Titrant is the solution in volumetric analysis whose concentration is known. Titrand is the solution in volumetric analysis whose concentration is to be found. (Solution with unknown concentration). Indicator is the substance used to observe the color change of the resulting solution. Equivalence point is the point which will show the color change of the resulting solution for the first time when adding solutions from burette drop wise. End point is the point at which the color change will not be disappeared and stay permanently. Phenolphthalein is used because it is slightly acidic and it can detect the pH range of 8.3 to 10.0 resulting color change colorless to pink. Phenolphthalein is insoluble in water where it is soluble is alcohols. (Matthews, 2003). Color change of Indicators (Phenolphthalein) (Pradeep and Dave, 2013) Preparation of 0.1moldm-3 of NaOH Took 10.0ml of NaOH (1moldm-3) to the graduated pipette using pipette filler and introduced it into the volumetric flask whose volume is 100ml. Then diluted the solution up to 100ml by adding distilled water until the lower meniscus of the diluted NaOH solution to tally with the ring mark present on the volumetric flask. Acid Base Titration is carried out to find the concentration of an acid or a base by neutralizing the acid or the base of which the concentration is unknown. The burette should be filled with the Base (known concentration solution) and the titration flask should contain the acid which the concentration is to be determined. Then three drops of indicator, phenolphthalein should be added to the titration flask, because the phenolphthalein will leads towards the color change in the resulting solution. In the titration above, the acid which has the unknown concentration is HCl and the base which has the known concentration is NaOH. When NaOH added with HCl, it results NaCl with H2O. Sodium hydroxide + Hydrochloric acid Sodium Chloride + Water NaOH + HCl NaCl + H2O After setting up the equipment, the titration is carried out by allowing base from burette to fall into the acid drop wise and should observed the resulting solution very carefully until it occurs the color change. At some point, when the NaOH drops falls into the HCl solution will result pink color due to phenolphthalein and that pink color is not permanent since it disappears. When observing the pink color for the first time, it will be the equivalence point. Then the test should be carried out so on until pale pink color will remain without disappearing and it is called the endpoint of the titration. Once endpoint is reached, tap of the burette should close soon and get stop the titration. Then tabulate the reading by repeating the experiment at least three times to get three readings. Finally calculate the concentration of the unknown solution by putting the reading into the basic equations of chemistry. Objectives: The objective of this practical is to find out the unknown concentration of an acid or a base by Volumetric Analysis which is a quantitative analytical method. Materials: Volumetric Flask Burette Funnel Graduated Pipette Transfer pipette Beakers Hydrochloric Acid Sodium Hydroxide Phenolphthalein Burette Holder Titration Flask Pipette filer Distilled Water Methodology: First the graduated pipette was washed with a small amount of Sodium Hydroxide (NaOH). Then the filled sodium hydroxide was discarded and 10.0 ml of NaOH was filled to the graduated pipette using pipette filler and transferred to a volumetric flask. A little amount of distilled water was poured into the volumetric flask and swirled. Then more distilled water was added up to the volumetric flask till it rises up to the ring mark and lower meniscus balanced. Cleaned the burette with small amount of NaOH. After that the burette was fixed vertically to the burette holder and the burette was filled up to 0.00ml mark. Then the graduated pipette was washed with some (Hydrochloric) HCl acid to clean up. After cleaning the graduated pipette by HCl acid, it was filled with HCl acid whose concentration is to be found, exactly up to 10.0 ml with the help of pipette filler. Then 10.0ml of HCl acid was introduced to the titration flask and three drops of phenolphthalein was directly put into HCl acid in the titration flask without let it touching the glass of the titration flask. After that, placed the titration flask under the burette which was fixed to the holder. The tap of the burette was slowly opened to release the NaOH drop wise into the titration flask, then at one place, the NaOH drops when fall into the HCl acid will show some pink color dot for the very first time, and that point will call as the equivalence point of the titration. Then the tap was adjusted slowly to reduce the rate at which it release NaOH drops. Few seconds later at a point the pale pink color can be seen which is permanent, and that point is called the end point. Then closed the tap of the burette and the volume of NaOH which has been used to neutralize the acid is recorded. After recording the first reading continued the practical two more times to get another two readings. Results were tabulated. Results: The experiment is carried out for three times to get three readings and reading taken at each test has been tabulated below. Average volume = 32.10cm3 + 34.00cm3 + 35.20cm3 3 = 33.76 cm3 Discussion: Titration is the process of determining the concentration of unknown solution when two solutions are put into to neutralize. A chemical reaction has been used for this purpose and the reaction should be fast and should be a complete reaction. The titration should have a determinable equivalence point and an endpoint. We used HCl and diluted NaOH (0.1moldm-3) in this titration process and the indicator used is phenolphthalein which can cover a range of 8.3 to 10.0 pH value. Here, the indicator is acting like a signal showing where to stop the titration at endpoint. When NaOH added with HCl, it results NaCl with H2O. Sodium hydroxide + Hydrochloric acid Sodium Chloride + Water NaOH + HCl NaCl + H2O Actually the endpoint is the neutral point where acid and base get neutralized. For this reaction, Ionic equation is: H+ + OH H2O Here at the endpoint in first titration, the whole resulting solution turned into pale pink color, but other two reading were too far apart due to some errors. The errors which may lead to deviate the readings may be: Improper calibration of glass wares Misreading the volume in graduated pipette Using of contaminated solutions Using of solutions with wrong concentrations Using indicators in wrong amounts Using impure glass wares Not transferring the proper volume and not taking the proper volume Not filling up the burette properly Using wrong solutions since all looks same (colorless) Sometimes it can be due to the usage of contaminated solutions because taking the pipette for the next test without washing. It can be due to the way which cleaned the pipette after using once. Sometimes the titration results can alter due to human errors such as difficulty with reading the burette value or sometimes hand glows can have some drops of some other solutions and get dropped to the test which is going on. As the first reading 32.10cm3 was a successful effort, but still the test 02 (34.00cm3) and test 03 (35.20cm3) was unsuccessful due to those errors. Sometimes the color change was so rapid change and unable to stop the tap of the burette on time. Conclusion: The concentration of the unknown was determined by using titration process and by the known value for the other solution. Calculation should be carried out in order to get the final answer to determine the unknown concentration of HCl. Calculation: Average volume = 32.10cm3 + 34.00cm3 + 35.20cm3 3 = 33.76cm3 Assumption: Number of moles remain unchanged Therefore by using, C1V1 = C2V2 0.100moldm-3 x 0.100dm-3 = C2 x 0.033dm-3 C2 = 0.100moldm-3 x 0.100dm-3 0.033dm-3 C2 = 0.30moldm-3 THE UNKNOWN CONCENTRATION OF HCl IS 0.30moldm-3 Reference: Pradeep, D.J. and Dave, K. (2013) ‘A Novel, Inexpensive and Less Hazardous Acid-Base Indicator’, Journal of Laboratory Chemical Education, 1(2), pp. 34-35. [Online] DOI: 10.5923/j.jlce.20130102.04 (Accessed 30 October 2014). Matthews, P. (2003) Advanced Chemistry. New Delhi: Cambridge University Press. Datta, S.C. and Johar, N.K. (2014) Undergraduate Chemistry. New Delhi: Anne Books Pvt.Ltd.

Is Tv the Cause of Violence in Today’s Society? Essay

TV has bad Impacts As we all know some TV programs are educational, they open our minds by providing information that are unlikely to be taught in schools and other places such as home-schooling But there are also some TV programs that are not so educational, which could affect us physically and emotionally. According to some research it was said that Television has a higher level of violence, in most of the cases these programs are being watched by young children which can be a negative influence and it could affects the children’s grades, sleep and daily activities. Kids are small and their minds haven’t developed yet, so when a child watches a show or a movie they usually copy everything that is being done on the screen, not even caring whether it’s good or bad. AS I said, when a child watches violence on TV they repeat what is being done, thinking that their action will not be punished, which means they are being persuaded that crimes, and violence don’t cause any harm. For example 47% of violent television programs show the victim being unharmed, especially in cartoons. Characters in cartoons and television shows get blowed over by another character and they get back up without being harmed, this makes children believe that violence doesn’t really hurt anyone. TV and Violance Television shows that allows the character who commits the crime to receive no punishment, allows children to learn that it is alright to commit a crime because nothing will be done. Television has no significant influence on an adult’s mind, but it has a major impact on children, and on their brain’s development. Most important of all, if children catch the idea of violence in childhood from TV, then their ideas and thoughts about crimes, murders, etc. can’t be changed. If we Watch too much television We begin to ignore the outer world, we become less social, our personality slightly begin to change negatively, and most of all we begin to have diseases such as refractive error of the eyes (especially near-sightedness), obesity, heart attack, spine disease, mental disorder, etc.,

Primate Society and Human Society Essay

The present paper is intended to discuss the similarities between the social behaviors of baboons and humans according to the book â€Å"Almost Human† by Shirley Strum. The first manifestation of social behavior Shirley Strum noticed is threat signals the animals convey when a newcomer appears (Strum, 1987, p. 24). Furthermore, as the newcomer approaches, juveniles and adult females circle around him and carefully examine him. The animals introduce themselves in an interesting way: â€Å"A female â€Å"presents† to a male when she approaches and turns her bottom toward his face; then the male will generally sniff her to see if she is sexually receptive. Two males can also present to each other with no sexual intention at all, and the same greeting is frequently exchanged by females, juveniles and even babies when they can manage it. † (Strum, 1987, p. 25). In several days upon the arrival of the newcomer, he remains an outcast, yet the other tribe members keep their eyes on each movement he makes. When a female comes closely to a male, the latter narrows his eyes, shakes head and smacks his lips – this physical manifestation is quite common among baboons. However, if the male is not considered â€Å"popular† in the group of animals, the female might simply flee without introducing herself, – then male continues grimacing as described above and accompanies the grim with soft grunting. The couple play this game for quite a long time – the female approaches and then quickly distracts and escapes, whereas the male continues to exhibit his â€Å"infatuation†. Such social â€Å"games† are played between men and women in our society. For instance, when a woman presents herself to a man, she smiles and shakes hands with him. They also verbally exchange their introductory information – name, occupation, hobbies. At the same time, the man, who considers marriage or searches for a sex partner, processes the information about the woman’s appearance and . If he is attracted to the woman, he begins to make slight hints and social gestures – e. g. , he might distinguish her amongst his friends and become more sincere, invite her to a theatre, cinema or dinner, give her gifts and flowers and so forth. However, if the woman notices the man has low social position or does not meet her social requirements, she is likely to lose interest in his â€Å"candidacy†. However, if the man persists and manages to present his interest as genuine and stable, the intimate relationship might begin. Human and baboon behaviors in cross-gender relationships are quite similar. Primarily, baboons present themselves to one another in order to learn more about a stranger; similarly, humans introduce themselves both verbally and through smiling, shaking hands. This introductory stage allows gathering the basic information and determining the primary sources of threat in the â€Å"interlocutor† (e. g. , contagious disease, among humans – armor etc). Among humans, smile acts as a sign of the person’s peaceful intentions, as humans are less proficient in the use and understanding of body language. Further, as a female baboon approaches the male and gives him an opportunity to inhale her odor, she shows to him that she is sexually mature and can have intimate contact. Moreover, such close introduction allows the male to examine her appearance, or â€Å"beauty† – this factor is extremely important, given that â€Å"beauty† in primate groups is associated with physical health and fitness. The healthier the female is the stronger progeny she can bear and the fewer problems with bearing and birth she will experience. Similarly, human males assess the female during the first seconds of encounter, – in particular, they pay attention to such criteria as age, physical beauty and erudition, as they half-consciously select (not always intentionally) a potential sexual partner or spouse and subconsciously believe younger (to reasonable degree, but generally younger in comparison to the male), smarter and more gorgeous women are fitter and better prepared for life in this society. Female baboons show their bottoms when they seek to lure a male, perhaps because appropriate building of this body part serves as a proof of the female’s sexual maturity and health. Human females, who wish to look â€Å"attractive†, also demonstrate their bodies, not necessarily naked, but always underlined by stylish clothes, make-up and accessories. After evaluating the female and determining whether she fits his criteria of physical development and appearance, the male baboon himself seeks to attract the female by displaying his interest and showing his own fitness and strength. Similarly to the primate society, among humans, there is also a behavioral pattern which consists in male’s responsibility for making the first step towards a stable relationship (e. g. inviting the woman he is infatuated with to a dinner, entertaining her, paying a lot of attention to her personality). If the female baboon realizes that male is outcast, she will continue ignoring him for some time, as the fittest males, whose inheritance will be most favorable to the future progeny in terms of survival, are normally popular in the tribe and have a high degree of authority. Furthermore, popular member of the tribe is more capable of providing for his female when she is consumed by â€Å"childcare†. Like female baboons, women become quite suspicious when meeting social outcasts or men of lower social status, who are potentially less likely to meet the needs of the family after the baby appears. However, in both societies, if the male manages to prove his dependability and keeps attending to the female for a long time, the latter might change her mind and find him eligible. As one can assume, human social behavior in cross-gender relationships is driven largely by instincts exhibited by primates. The factors humans and primates consider when selecting a sexual partner are in many cases the same, as males of both groups first and foremost evaluate physical fitness, whereas females in both baboon and human societies make a more complex analysis and also look at the male’s social position envisioning the necessity of taking care of defenseless and dependent progeny (or children). Both humans and animals are greatly concerned about the physical characteristics of the next generation, which partially backs Darwin’s theory of the survival of the fittest and the inborn striving for the survival of the species.

Effects of Technology on the Cognitive and Physical...

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(Raising Children Networks, 2014) state that, it’s particularly ‘helpful if you get involved with your child and her use of media – for example, you can visit quality websites together, encourage use of educational software, and view TV shows offering extra learning opportunities.’ This leads to engagement with the content e.g. repeating and acknowledgement of words, numbers and objects, decision making skills. Even from a young age babies can develop knowledge for culture, problem solving skills and an early grasp of technology use, which will largely shape the generatio n they live in. Downsides are also present towards your baby using technology. 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