Primary Standards in Chemistry

Primary Standards in Chemistry In chemistry, a primary standard is a reagent which is very pure, representative of the number of moles the substance contains and easily weighed. A reagent is a chemical that is used to cause a chemical reaction with another substance. Often, reagents are used to test for the presence or quantity of specific chemicals in a solution. Properties of Primary Standards Primary standards are typically used in titration to determine an unknown concentration and in other analytical chemistry  techniques. Titration is a process in which small amounts of a reagent are added to a solution until a chemical reaction occurs. The reaction provides confirmation that the solution is at a specific concentration. Primary standards are often used to make standard solutions (a solution with a precisely known concentration). A good primary standard meets the following criteria: high level of puritylow reactivity (high stability)high equivalent weight (to reduce error from mass measurements)not likely to absorb moisture from the air (hygroscopic) to reduce changes in mass in humid versus dry environmentsnon-toxicinexpensive and readily available In practice, few chemicals used as primary standards meet all of these criteria, although its critical that  a standard is of high purity. Also, a compound which may be a good primary standard for one purpose may not be the best choice for another analysis. Examples of Primary Standards and Their Uses It may seem odd that a reagent is needed to establish the concentration of a chemical in solution. In theory, it should be possible to simply divide the mass of the chemical by the volume of the solution. But in practice, this isnt always possible. For example, sodium hydroxide (NaOH) tends to absorb moisture and carbon dioxide from the atmosphere, thus changing its concentration. A 1-gram sample of NaOH may not actually contain 1 gram of NaOH because additional water and carbon dioxide may have diluted the solution. To check the concentration of NaOH, a chemist must titrate a primary standard (in this case a solution of potassium hydrogen phthalate (KHP). KHP does not absorb water or carbon dioxide, and it can provide visual confirmation that a 1 gram solution of NaOH really contains 1 gram. There are many examples of primary standards; a few of the most common include: Sodium chloride (NaCl) is used as a primary standard for silver nitrate (AgNO3) reactions.Zinc powder may be used to standardize EDTA solutions after it has been dissolved in hydrochloric acid or sulfuric acid.Potassium hydrogen phthalate or KHP may be used to standardize perchloric acid and an aqueous base in an acetic acid solution. Secondary Standard Definition A related term is secondary standard. A secondary standard is a chemical that has been standardized against a primary standard for use in a specific analysis. Secondary standards are commonly used to calibrate analytical methods. NaOH, once its concentration has been validated through the use of a primary standard, is often used as a secondary standard.

What is the burden of proof for civil case and a criminal case Assignment

What is the burden of proof for civil case and a criminal case - Assignment Example This is owing to the fact that the defendant stands to be jailed and lose other civil liberties in criminal cases. Owing to the penalties that are associated to criminal cases, the prosecution is charged with the duty of more than proving that the defendant committed the crime in question, it must be beyond reasonable doubt (Finkelman, 2006). In other words, the evidence presented against an individual should be adequate that no rational person can question their guilt. In addition to proving the guilt of the accused, the prosecution is required to prove that there was intention to commit the crime. In instances where the prosecution does not satisfy both requirements, the accused cannot be convicted. When dealing with a criminal case the burden of proof is on the state at all instances. It is upon the state to prove the defendant’s guilt. On the other hand, the defendant is viewed to be innocent and has nothing to prove (Finkelman, 2006). However, there are exceptions in instances where the defendant is under duress or self-defense and instances of insanity. Furthermore, the state should establish that the defendant satisfied every stipulation in the appropriate definition of crime. In spite of the fact that the concept is mostly linked to criminal litigation, it is applicable to civil litigation that relates to personal injuries, contracts and property issues. The plaintiff is required to have sufficient evidence to back their accusations while on the contrary the defendant must prove these accusations to be wrong. In civil cases, the burden of proof is originally on the plaintiff. However, there are various technical cases whereby the burden of proof is tranferred to the defendant. For example, in situations where the plaintiff has filed for a prima facie case, the burden of proof is tranferred to the defendant (Finkelman, 2006). In civil cases, the plaintiff wins if

Reflection paper Essay Example | Topics and Well Written Essays - 500 words - 37

Reflection paper - Essay Example It is important for me to know who I am and to acknowledge my identity. It also helps me to determine my strengths and weaknesses. This was the most interesting yet most difficult lesson to let sink in. Though I know that self-concept is an essential part of life, it is hard to look at your own strengths and weaknesses. I know now what some of those are and the areas that are my weaknesses are those that I can work on and learn from. It is not as simple as looking at yourself in the mirror but more like looking at yourself under a microscope and sometimes what you see is difficult. That is also where I had several â€Å"aha† moments. It sounds narcissistic to only acknowledge what I learned about myself but it is difficult to build on anything else in communication without acknowledging my own strengths and weaknesses in life. The HURIER method was also a great thing to learn because it helped me learn more about listening. Sometimes I find myself busy and thinking about other things that I have to do that I sometimes may drift off and think about other things when I am in the middle of a conversation or even in class. I may be hearing someone else but I am not listening. This lesson helped me to realize I need to stop what I am doing and listen or the translation of what I hear can be completely different than the message I was supposed to be hearing. I know that I need to go through the steps of hearing, understanding, remembering, interpreting, evaluating and responding, hence the acronym. In any conversation or giving an answer in class, I have to actually hear and process the message in order to give an appropriate response to what it is I have heard. I think it is a tool that I use without thinking about it but actually seeing it in a logical organizational form makes it easier to remind myself that I need to really think things through before responding. The elements that make me a bad

How does new technology affect education Essay Example | Topics and Well Written Essays - 500 words

How does new technology affect education - Essay Example Currently, the education sector is experiencing a rapid transition whereby different disciplines are embracing Tablet PCs as well as similar pen-based gadgets. This is to enhance both teaching and learning processes, which is contrary to the past whereby their respective modes encompassed physical interaction between the student and tutors. Evidence of the emerging impact of new technological knowhow was quite evident in 5Th workshop held in Virginia in 2010. This was through varied presentations by different intellectuals whose information comprises this book. For the past eight decades in 20Th period before 1980s, educated worker’s curve depicted an upward trend. However, the demand for them was not that high as compared to the current state, which is the contrary. Due to high education before 1980s, this prompted to the emergency of numerous people who were well off, hence becoming the richest region globally. However, that trend currently has ceased whereby due to the rapid technological change states are facing the shortage of skilled labour force. Introducing technological knowhow to children is of great importance in ensuring they are ready to tackle other varied aspects during their education. This is especially in tackling varied subjects as well as doing researches at a later period, which is more beneficial compared to when they learn of using technology later. However, this takes the effort of well trained tutors in the mode of implementing technology as per the children or student’s capability, which Casey outline in this book. Implementing in this case encompasses considering 90 activities, which Casey advocates in this research for each child starting from as early as three years. The source offers detailed information meant to equip any learning person with necessary studying and leadership skills. The former skills encompass confidence, creativity and being able to navigate the constantly evolving environment due to emergent

The History Of The Family Systems Theory Sociology Essay

The History Of The Family Systems Theory Sociology Essay The definition of Family has become increasingly controversial over the past few decades. Family in the twenty-first century is different to everyone; all families have different structures and functions, beliefs and parental attitudes. The term family refers to a unit consisting of people who are related to each other either biologically by notions of blood relations, or alternatively by legal means such as by marriage (Kirby, et al 2000, p45). The definition of a family has changed a lot over the years; there are several reasons for the definition to change. The view of the typical nuclear family is no longer the norm within society. Nowadays there are more families of divorce, stepfamilies, and extended families, rich and poor families. There is not a single definition for what a family is; people have their own view of what a family is. There are many factors that make families different, such as ethnicity, religion, and economics. Levine (N.D) suggests that families have three basic goals for the children; survival, economic self-sufficiency and self-actualization (Enrique, et al, 2007) Family structure and family functioning can affect a childs development in many ways. Family structure is the way in which a family is set up, for example, single parent families, extended families and nuclear families. Family functioning refers to how family members are emotionally attached, how well they communicate emotions and information and respond to problems (Freistadt and Stohschein. 2012). Everyone has a different view of what family is and how families should be structured. Some make the assumption that children can only be brought up successfully in a two-parent family structure involving a heterosexual relationship. Others take the perspective that children can function well in any family structure, provided certain basic conditions are met (Wise, 2003). According to Schaffer family structure plays less importance part in a childs development than family functioning. The family is a social system endorsed by law and custom to take care of its members needs (Kepner, 1983). The emotional bondings and relationships between the members of the family, and their responsibility to the family unit hold them together through the changes of transitions and the complicated connections. Family Systems Theory Murray Bowen developed the family systems theory, he recognised that the family was an emotional unit and any changes to the family functioning would influence all members of the family. The family systems theory emerged from the general systems theory by scholars who found that it had a lot of relevance to families and other social systems. http://web.pdx.edu/~cbcm/CFS410U/FamilySystemsTheory.pdf The family systems theory refers to a family as a system in which each member can never be considered in isolation without reference to the roles, responsibilities and behaviours of other members of the family. The family is seen a dynamic unit according to the family systems theory. Changes are constantly occurring and each member of the family takes on new roles and responsibilities, and internal patterns are adopted. The relationships between the individuals in the family unit are mutual and constantly changing. The family is an example of an ongoing, self-regulating, social system that has certain features such as its unique structuring of gender and generation set it apart from other social systems. Each family system has their own structure, the psychobiological characteristics of its individual members, and its sociocultural and historic position in its larger environment (Broderick, 1993, p37). The family as a system links all individuals together and understands that things going on in the environment can influence all individuals even if not all of them are actively engaged, for example parents workplace. The family system theory recognises that small things can impact the family system, for example, the loss of a parent can affect the relationship the child has with the other parent and/or siblings. http://www.edpsycinteractive.org/papers/family.pdf According to Bowen each member of the family system has a roles and boundaries. Individuals in the system are expected to engage with each other in a certain ways according to their role and their relationship with other members. There are four main principles of the family systems theory; wholeness, integrity of subsystems, circularity of influence and stability and change. Wholeness refers the family as one unit however each member of the family have certain attributes of their own. Integrity of subsystems means that each relationship is a subsystem, for example; mother and father relationship or mother and child relationship or vice versa. Relationships between relationships are also subsystems. Circularity of influences means that the subsystems and relationships depend on each other and if there is a change in one subsystem it has an impact on other systems. Stability and change refers to external influences that can affect the individual or subsystems, for example parents workplace. The wellbeing of the child, therefore, can be conceived of as dependent upon the functioning of elements of the entire family system (McKeown and Sweeny 2001: 6) Family systems are different in all families. Parental attitudes are important in setting up an environment in which their child can flourish. Campion (1985) says that if a child grows up in a stable and loving environment, the child will usually develop a sense of self-respect and self-discipline. The child understands what is expected of him and However it can be argued that a child who has been brought up in a family system where the parents attitudes lack maturity, the child is more likely not to flourish in the environment and not understand what is expected of them, therefore cannot develop a sense of their own competence. Campion (1985) suggests that children take on the roles, which have a function in their family system. It is believed that if children see themselves as the disobedient one in the family setting, they may carry out their difficult behaviours in school. Likewise a child who is obedient may also carry out this behavior at school. The ecological systems theory Bronfenbrenners ecological systems theory states that the environment is reflected in an individuals development. Bronfenbrenners ecological approach refers to layers of environmental influences that impact an individuals development. The interactions with people and the environment are key to development. This theory can apply to individuals at any stage of development. The theory identifies five environmental systems in which the individual interacts with; microsystem, meosystem, exosystem, macrosystem and chronosystem. The microsystem refers to each setting, which the individual is an active participant, such as; family, school, community, friends. This layer has the most immediate and earliest influences on the child. The relationships in the microsystem can be bi-directional; this means that the childs behaviours can be influenced by the family and vice versa. The meosystem refers to the relationships between the settings in the microsystem and the individual; an example of this would be the relationship between home and school. The exosystem refers to a setting or setting where an event happens, which affects or is affected by what happens in the setting that the developing person is in. The child is not an active participant in this system. The structures in the exosystem can affect a childs development by interacting with the structures in the microsystem, for example; mothers work place can affect the amount of time the mother spends with the child. Although the child is not directly involved with the structures in the exosystem, they do feel the positive and negative impacts that are involved with the interaction between the systems. The Macrosystem refers to the wider social systems, for example; government legislations and economic factors. These things affect the child indirectly however it has an impact on the developing childs life. An example of this could be that the childs family is living in poverty therefore this can cause social exclusion and the child might not have access to school trips or community play areas. The chronosystem refers to how things change over time as it relates to the childs environment. There are various elements within this system that can be internal or external. An internal influence could be the physiological changes that occur while the child gets older. An external influence could the timing of their parents getting a divorce. The older the individual gets might impact how they react to environmental changes and may be able unders tand how the change will influence them. External influences

Colonialism in the Caribbean Essay -- Socio-Cultural Areas History Cul

Colonialism in the Caribbean Although Michelle Cliff, Antonio Benitez- Rojo, and Sidney Mintz all discuss the Caribbean in their writings they all have very distinct perspectives. In his writing, The Caribbean as a Socio-cultural Area, Sidney Mintz discusses the Caribbean from a historical standpoint in which he characterizes it as a socially united, rather than a culturally united one. Antonio Benitez- Rojo tries to explain the distinct cultures of the Caribbean with a combination of historical and personal knowledge , in his writing of The Repeating Island. While in her novel Abeng, Michelle Cliff uses an entirely different means of discussing the Caribbean because she does it through the eyes of a child. Despite having different outlooks in explaining the Caribbean they all record the theme of colonialism and their effects on people and society. Mintz's Perspective The Caribbean as a Socio-Cultural Area addresses the current cultural Caribbean with an eye on the past. For example, when discussing the emergence of creole culture Mintz specifically points out that this was almost exclusive to the islands colonized by the Spanish. According to Mintz, the Hispanic Caribbean was "settled by Europeans who had come to stay and to become "creoles"; nowhere and at no time in the Hispanic islands did African slaves ever outnumber freeman of European origin" (Mintz 28). Therefore, contemporary Puerto Rico, Dominican Republic, and Cuba are all very culturally diverse places who all have distinctive combinations of African, Native American, and European influences. For historical reasons, different regions of these islands have developed their own local cultures and social atmospheres by virtue of the types of people who lived ther... ... to her colonizers land reveals Jamaica’s present dependence England and the United States which is an effect of colonialism. It is the combination of readings from Mintz, Rojo, and Cliff which have explained what colonialism did in forming of the contemporary Caribbean. Also, not all of these islands are the same culturally because of the variety of colonial power imposed. Ultimately, it is impossible to look beyond this influence today because the structures of these islands are in fact the remains of colonialism. References Benitez-Rojo, Antonio. The Repeating Island, as seen in Post-contemporary Interventions, Duke University, Durham and London, 1992 Cliff, Michelle. Abeng. Published by the Penguin Group, 1984. Mintz, Sidney W. The Caribbean as a Socio-Cultural Area, as seen in Peoples and Cultures of the Caribbean, Garden City, New Jersey, 1971. Colonialism in the Caribbean Essay -- Socio-Cultural Areas History Cul Colonialism in the Caribbean Although Michelle Cliff, Antonio Benitez- Rojo, and Sidney Mintz all discuss the Caribbean in their writings they all have very distinct perspectives. In his writing, The Caribbean as a Socio-cultural Area, Sidney Mintz discusses the Caribbean from a historical standpoint in which he characterizes it as a socially united, rather than a culturally united one. Antonio Benitez- Rojo tries to explain the distinct cultures of the Caribbean with a combination of historical and personal knowledge , in his writing of The Repeating Island. While in her novel Abeng, Michelle Cliff uses an entirely different means of discussing the Caribbean because she does it through the eyes of a child. Despite having different outlooks in explaining the Caribbean they all record the theme of colonialism and their effects on people and society. Mintz's Perspective The Caribbean as a Socio-Cultural Area addresses the current cultural Caribbean with an eye on the past. For example, when discussing the emergence of creole culture Mintz specifically points out that this was almost exclusive to the islands colonized by the Spanish. According to Mintz, the Hispanic Caribbean was "settled by Europeans who had come to stay and to become "creoles"; nowhere and at no time in the Hispanic islands did African slaves ever outnumber freeman of European origin" (Mintz 28). Therefore, contemporary Puerto Rico, Dominican Republic, and Cuba are all very culturally diverse places who all have distinctive combinations of African, Native American, and European influences. For historical reasons, different regions of these islands have developed their own local cultures and social atmospheres by virtue of the types of people who lived ther... ... to her colonizers land reveals Jamaica’s present dependence England and the United States which is an effect of colonialism. It is the combination of readings from Mintz, Rojo, and Cliff which have explained what colonialism did in forming of the contemporary Caribbean. Also, not all of these islands are the same culturally because of the variety of colonial power imposed. Ultimately, it is impossible to look beyond this influence today because the structures of these islands are in fact the remains of colonialism. References Benitez-Rojo, Antonio. The Repeating Island, as seen in Post-contemporary Interventions, Duke University, Durham and London, 1992 Cliff, Michelle. Abeng. Published by the Penguin Group, 1984. Mintz, Sidney W. The Caribbean as a Socio-Cultural Area, as seen in Peoples and Cultures of the Caribbean, Garden City, New Jersey, 1971.

Black Codes Essay

The black codes were a another word for hate, and the reason I say this because the true meaning of The black codes is a law that stops the blacks from having freedom, and later on they would begin to Force them into owing or as I was taught debt. With legal prohibitions of slavery ordered by the Emancipation Proclamation, acts of state legislature, and eventually the Thirteenth Amendment, Southern states adopted new laws to regulate Black life. This was a very serious law for the blacks it was Mean and made them seem like they weren’t people just like they did the grandfather clause and I say This wasn’t a very good matter. This was like the grandfather clause the code is to watch the movement From theirs to the south some laws say black can’t hold guns and cant trade produce and they said this To want them back on the plantation. â€Å"The black codes were passed by the ex-confederate states after the civil war, the purpose of the Black codes were to keep freed slaves in a servitude state, to ensure cheap agricultural labor, and to Keep a white dominate position†. Yes I say they are right because through the research I found this was The one most popular it was well written it talks about cause it talks about what I said in the first Paragraph. Example; Arkansas passed a law prohibiting colored people to Immigrate to Arkansas Another example is Texas required railroad companies to have separate cars for Black and white people And my last example is Arkansas required separate schools for white and black People, they also made a Law called the vagrancy law which meant â€Å"Any person that a law enforcement Officer or judge deemed To be unemployed and not owning property could be arrested and charged as a Vagrancy†. -History. com Radical Republican Reconstruction efforts from 1866-1867, and passage of the Fourteenth Amendment and civil rights legislation, helped to greatly eliminate the Black codes. The Union victory in The Civil War may have given some 4 million slaves their freedom, but African Americans faced a new Onslaught of obstacles and injustices during the Reconstruction era (1865-1877). By late 1865, when the 13th Amendment officially outlawed the institution of slavery, the question of freed blacks’ status in the Postwar South was still very much unresolved. The Freedmen’s Bureau also helped the former slaves in the workplace. It tried to make sure that The former slaves received fair wages and freely choose their employers. The bureau created special The bureau created special Courts to settle disputes between black workers and their white Employers. It could also intervene in other cases that threatened the rights of freedmen. The South Carolina code included a contract form for black â€Å"servants† who agreed to work for white masters. The Form required that the wages and the Term of service be in writing. The contract had to be witnessed And then approved by a judge. Other Provisions of the code listed the rights and obligations of the Servant and master. Black servants had to Reside on the employer’s property, remain quiet and orderly, Work from sunup to sunset except on Sundays, and not leave the premises or receive visitors without the Master’s permission. Masters could moderately whip servants under 18 to discipline them. Whipping Older servants required a judge’s Order. Time lost due to illness would be deducted from the servant’s Wages. Servants who quit before the end date of their labor contract forfeited their wages and could be Arrested and returned to their Masters by a judge’s order. On the other hand, the law protected black Servants from being forced to do Unreasonable tasks. This is how the 1800’s were they were very mean, cruel and they never thought about anybody But there self and I think that the black codes is just a distraction from what they really and I say that They are all people the black the whites and all the other races it just took them long enough to realize That and I say that is very poorly of them because doesn’t matter what you look like or what you wear Or what your skin color is people are people and we all need to accept that. This is the reason why I Chose the black codes there is no other reason I chose it because people found out the truth that we are A Special in different ways and I like the way we get along to day without racism.