Electrochemical Cell Essay Example for Free

Electrochemical Cell Essay Introduction To investigate the effect of change in temperature of the solutions on the voltage of an electrochemical cell. How does increase in temperature of the electrolytes in en electrochemical cell affect the voltage? An electrochemical cell produces electrical energy from chemical energy, where the chemical energy comes from the reactions in the cell. An electrochemical cell consists of two half-cells. Each half-cell consists of an electrode, and an electrolyte (salt solution). A salt bridge is used that connects the two solutions in the containers to allow flow of ions so there is no charge build up in either solution. Charge build-up would shift the equilibrium and the reaction would cease. When the two half cells, consisting of a metal electrode and a conducting solution are connected with an external wire, the strongest oxidizing agent will undergo a reduction in one half cell and the strongest reducing agent will undergo an oxidation in the other half cell. An electrochemical cell makes use of a redox reaction and uses the chemical reaction to produce an electric current. The two metals that will be used in this experiment are Copper and Zinc, and their salts are used in an aqueous form in the container, being CuSO4 and ZnSO4. A salt bridge that is dipped in KNO3 will be used. The following reaction takes place in each half cell: Cu (s) Cu2+ (aq) + 2e- Zn (s) Zn2- (aq) + 2e- Independent Variable: Temperature of the electrolytes (à ¯Ã‚ ¿Ã‚ ½C) Dependant Variable: Voltage (V) Controlled Variables: Nature of electrodes: The electrodes will be of the same elements i.e. Copper and Zinc. Changing the nature of the electrodes will change the voltage since different elements produce different forms of ions which then affects the voltage of the cell. Size of electrodes: The size of electrodes will be kept constant to 6cm x 1cm. Increasing the size of electrodes means that the electrodes will react produce more ions hence increasing the voltage of the cell. Nature of ion transfer: A salt bridge (dipped in KNO3) will be used as a pathway for the ion transfer between the two half cells. Changing the nature of ion transfer will change the amount of ions are transferred between the half cells hence affecting the voltage. The concentration of the electrolytes: is kept constant. A constant amount of metal salt will be added to make each electrolyte. Having a varying concentration will affect the amount of ions produced hence varying the voltage accordingly. Voltmeter: The voltmeter is kept constant since changing the voltmeter can affect the voltage since different voltmeters may have different resistance which may affect the readings. Materials required * Copper strip, 6cm x 1cm * Zinc strip, 6cm x 1cm * CuSO4 solution, 0.99M à ¯Ã‚ ¿Ã‚ ½ 0.01M * ZnSO4 solution, 0.99M à ¯Ã‚ ¿Ã‚ ½ 0.01M * KNO3 solution, 1.99M à ¯Ã‚ ¿Ã‚ ½ 0.01M * Distilled water, 300mL à ¯Ã‚ ¿Ã‚ ½ 1mL * Beakers (3), 250mL à ¯Ã‚ ¿Ã‚ ½ 50mL * Graduated cylinder (100mL à ¯Ã‚ ¿Ã‚ ½ 1mL) * Digital Voltmeter with crocodile wires * Hot plate * Thermometers (2), à ¯Ã‚ ¿Ã‚ ½ 1à ¯Ã‚ ¿Ã‚ ½C * Paper strips, 10cm x 1cm * Magnetic stirrer * Rubber gloves * Apron * Safety Goggles Method Method to prepare solutions 1. Concentration required (CuSO4): 0.99M AMU of CuSO4: 159.61 So, 1.00M of CuSO4 has 159.61g of CuSO4 Hence 0.99M has: 159.61 x 0.99 = 158.01g à ¯Ã‚ ¿Ã‚ ½ 0.01g Mix 158.01g à ¯Ã‚ ¿Ã‚ ½ 0.01g of CuSO4 in 100mL of distilled water. Use a magnetic stirrer if necessary == Use 100mL à ¯Ã‚ ¿Ã‚ ½ 1mL of 0.99M à ¯Ã‚ ¿Ã‚ ½ 0.01M of CuSO4 solution. 2. Concentration required (ZnSO4): 0.99M AMU of ZnSO4: 161.44 So, 1.00M of CuSO4 has 161.44g of ZnSO4 Hence 0.99M has: 161.44 x 0.99 = 159.83g à ¯Ã‚ ¿Ã‚ ½ 0.01g Mix 159.83g à ¯Ã‚ ¿Ã‚ ½ 0.01g of ZnSO4 in 100mL of distilled water. Use a magnetic stirrer if necessary == Use 100mL à ¯Ã‚ ¿Ã‚ ½ 1mL of 0.99M à ¯Ã‚ ¿Ã‚ ½ 0.01M of ZnSO4 solution. 3. Concentration required (KNO3): 1.99M AMU of CuSO4: 101.11 So, 1.0M of CuSO4 has 101.11g of KNO3 Hence 1.99M has: 101.11 x 1.99 = 201.21g à ¯Ã‚ ¿Ã‚ ½ 0.01g Mix 201.21g à ¯Ã‚ ¿Ã‚ ½ 0.01g of KNO3 in 100mL of distilled water. Use a magnetic stirrer if necessary == Use 30mL à ¯Ã‚ ¿Ã‚ ½ 1mL of 1.99M à ¯Ã‚ ¿Ã‚ ½ 0.01M of KNO3 solution. 4. Now put the paper strip (salt bridge) in the KNO3 solution and leave it for 30 seconds. Method for investigation 1. Before starting the experiments, all the materials should be acquired with all safety precautions 2. Put the two beakers that have electrolytes on the hot plate. 3. Now put the salt bridge between the beakers. Also, put the two thermometers in each container 4. Connect the crocodile wires from the voltmeter to each electrode, but dont put it in the half cells yet. 5. Now turn on the hot plate and let the temperature increase from room temperature to 30à ¯Ã‚ ¿Ã‚ ½C 6. As soon as the temperature increases to 30à ¯Ã‚ ¿Ã‚ ½C, quickly insert the electrodes in the respective solutions (Cu in CuSO4 and Zn in ZnSO4) and record the voltage 7. Remove the electrodes and clean and dry them. 8. Now increase the temperature by a difference of 10à ¯Ã‚ ¿Ã‚ ½C i.e. 40à ¯Ã‚ ¿Ã‚ ½C, 50à ¯Ã‚ ¿Ã‚ ½C, 60à ¯Ã‚ ¿Ã‚ ½C, 70à ¯Ã‚ ¿Ã‚ ½C, 80à ¯Ã‚ ¿Ã‚ ½C and 90à ¯Ã‚ ¿Ã‚ ½C and repeat steps 5-7. 9. After the experiment has been completed, put the cleaned materials back to their original place. Raw Data Table Volume of each electrolyte (mL à ¯Ã‚ ¿Ã‚ ½ 1mL) Length of salt bridge (cm à ¯Ã‚ ¿Ã‚ ½ 0.01 cm) Length of each electrode (cm à ¯Ã‚ ¿Ã‚ ½ 0.01 cm)

Rights Of Egyptian Women Essay -- essays research papers fc

Rights of Egyptian Women Throughout written history, women have experienced status subservient to the men they lived with. Generally, most cultures known to modern historians followed a standard pattern of males assigned the role of protector and provider while women were assigned roles of domestic servitude. Scholars speculate endlessly at the cause: biology, religion, social custom. Nevertheless, the women were always subordinated to the men in their culture. Through their artwork, tomb inscriptions, and papyrus and leather scrolls, preserved in the dry, desert air, Ancient Egyptians left evidence for scholars suggesting that Egypt was once a peculiar exception to this pattern. Anthropological evidence suggests that unusual circumstances in Ancient Egyptian culture provided for women to be given equal status to their male counterparts: notably, matrilineal inheritance and emphasis on the joy of family life over maintaining ethnic purity. Legally, women in Ancient Egypt held the same legal rights as men. A woman could own property and manage it as she saw fit. One example of this, the Inscription of Mes, provided scholars with proof that women could manage property, institute litigation, and could act as a witness before a court of law. Surviving court documents not only showed that women were free to take action with the court, but the documents also show that they frequently won their cases. They could also enter contracts and travel freely, unescorted, throughout the state. This is a great contrast to women in Greece, who were required to act through a male representative. Interestingly, property and its administration was passed from mother to daughter, matrilineally. The Egyptians relied on matrilineal heritage, based on the assumption that maternal ancestors are less disputable than paternal ones. The effect of legal equality in writing and practice coupled with the ownership and administration of property led to an ensured equality. The rights and egalitarian conditions enjoyed by Egyptian women shocked the conquering Greeks. In 450 BC, Greek historian Herodotus noted: They Egyptians, in their manners and customs, seem to have reversed the ordinary practices of mankind. For instance, women attend market and are employed in trade,... ...providing scholars with an examples of conditions that brought about a particularly benign development of male-dominance in Ancient Egypt. Sources Cited: Tansey, Richard. Gardner's Art Through the Ages. Fort Worth: Harcourt Brace Publishers, 1996 91-93. Tyldesley, Joyce. Daughters of Isis. New York: Penguin Books Ltd, 1994. Bibliography Ahmed, Leila. Women and gender in Islam: historical roots of a modern debate. London: Yale University Press, 1992. Lesko, Barbara S. Women's Earliest Records. Atlanta, GA: Scholar's Press, 1989. Piccione, Peter A. "The Status of Women in Ancient Egyptian Society" History of Ancient Egypt Page. http://www.library.nwu.edu/class/history/B94/B94women.html 16 Oct, 1996 Robins, Gay. Women in Ancient Egypt. London: British Museum Publications, 1993. Tucker, Judith E. Arab Women: Old Boundaries, New Frontiers. Indianapolis: Indiana University Press, 1993. Tyldesley, Joyce. Daughters of Isis. New York: Penguin Books Ltd, 1994. Unesco. Social Science Research and Women in the Arab World. London: Frances Pinter, 1984. Watterson, Barbara. Women in Ancient Egypt. Great Britain: Alan Sutton Publishing, 1991.

History Comparison Betwen Mexican and African Americans Essay

The history of Mexican Americans is comparable to that of African Americans: filled with stories of conquest, racism, and discriminatory acts posed by society. The past has triggered Chicanos to fight back against injustices, in hopes of reforming immoral treatment, and emerging as an equal part of America’s society. The Chicano movement yielded some successes in this aspect. However, mass media and stereotypes confirm the notion that Mexican Americans are still viewed as a â€Å"lesser† people. This stems from the long-established concept of racial stratification. In this case, it indicates that Anglo-Americans have hierarchy over Mexican Americans. Consequently, discrimination towards Chicanos is still prevalent, despite ongoing efforts by activists for change. This nation was socially molded based on the idea that there is a hierarchy of races, and as long as that idea exists, Mexican Americans will continue to suffer inequality. In â€Å"Sexual Violence in the Politics of Conquest’, Castaneda explores the sexual crimes against Amerindian women during the Spanish conquest of Alta California. The soldiers accompanying the missionaries on the settlement raped and violated the native women openly. There were many incidents before rules were set to govern the matter, but even after the rapes continued to occur. One court case recorded in 1773 indicates that there was no intention to grant justice to the victims. The natives took matters into their own hands and formed forces to seek their own justice (similar to Chicano activist groups that seek reform for discrimination), but to no avail. Castaneda goes on to explain that the actions of the soldiers were not farfetched from practices of Western civilization (27-28). Because these dark crimes were normal for the dominant culture, they were automatically imposed on the natives, who were supposed to accept this without resistance. This is similar to Mexican Americans during the Chicano movement, who were not given equal opportunities for education and employment because they were not in the central group. In both situations, the majority emasculates the men and oppresses the women of the minority. The idea of hierarchy is apparent in this passage; Catholic missionaries try to strip the natives of their culture and convert them to value Western practices because they consider themselves the ‘prominent’ people. The history of the Chicano Movement can date back to the Manifest Destiny. In the 1840s, the United States planned to expand its territory and take Mexico, which had become independent from Spain. In reporting these events, Leo Cervantes notes the attitude of superiority that the Americans displayed in their imperialist plan. He notes one adherent’s thoughts, who asked â€Å"why resign this beautiful country to the custody of the ignorant cowards who have ruled for the last 25 years? † (13). Cervantes also quotes Thomas Jefferson, who has similar views of the matter, and promoted â€Å"policies of non-miscegenation† during the expansion (14). Even before Anglo-Americans were acquainted with Mexicans, they held predisposed opinions of contempt for them. As I suggested, Arturo Rosales agrees, â€Å"An underlying cause for the hostility Anglo-Americans felt for Mexicans was a preexisting ideology of racism† (5). These preconceived notions of Mexican Americans were the beginning of negative stereotypes attached to them. Today Chicanos are often represented in the media as uneducated thugs, loose women, or undocumented workers. Even whites who claim they are not racist may practice aversive racism by absorbing the images portrayed in media. It is this ideology of racism has contributed to discrimination over the years and inversely, the building of the Chicano Movement. The movement flourished in the 1950s and 1960s, feeding off other civil rights movements, particularly the African American movement. Both African American civil rights activists and Chicano activist protested the unlawful repression of minorities in America. They protested the terrible education system, police brutality, and denial of economic opportunities. Arturo Rosales compares Chicano activist, Cesar Chavez to Martin Luther King. It is expected that on this path to address the plight and repression of their people, Chicanos were met with resistance from White Americans. Rosales notes that police officers and other uniformed officials â€Å"were employed to suppress manifestations of discontent and did so using violence† (xv). It can be suggested that Anglo-Americans considered Chicanos a threat to the racial hierarchy, so they took action. Cervantes supports this theory, quoting Brooks Adams who said, â€Å"When a highly centralized society disintegrates, under the pressure of economics condition, it is because the energy of the race has been exhausted (18). This point illustrates the pressure Anglo-Americans felt to keep superiority over Mexicans. The American achievement ideology suggests four points: Anyone can make it. American society is fair and open. Success is based on merit. Moreover, inequality is the result of differences in ability and ambition. This ideology contradicts the apparent effects of a racial hierarchy. Stratification of races has formed structural discrimination among minorities, specifically, Mexican and African Americans. The poor education, poor neighborhoods, and badly equipped jobs that these minorities are subjected to prevent them from achieving upward mobility. However, white America still neglects to acknowledge these factors. Historian, Oscar Lewis, believed that people living in poverty are to blame for their own situation, yet minorities’ history in America consists of repression and treatment as inferior beings. There is no questioning it; racial classes have been socially constructed and this has directly affected minorities. The Chicano Movement has led to some advances for Mexican American such as the growing numbers of Latinos attending school, and raise concerns about unequal treatment to Chicanos. However, because underlying values of America are products of a deep-rooted, corrupt social structure, issue of prejudice will continue to exist.

The Life of Rodolfo Rodolfo Speedy Gonzales Free Essay Example, 1500 words

Due to Gonzales financial status, he diverted and pursued sports instead of a college education. He started his career as a boxer, first as an amateur. He was very successful at it, winning several titles and earning him fame nationwide. This boxing success gave him a great advantage when he began his career in the line of political affairs. He ran for Colorado State Representative in 1960 and for Denver Mayor in 1967 but was defeated in both campaigns. This was the last of his political endeavors. In between these two political campaigns, he deviated and supported Kennedy for the presidency and coordinated the Viva Kennedy campaign. This led to the most number of Mexican American registrations in the history of Colorado. By the 1960s, Gonzales led the Chicano Movement. They pushed and fought for the equality of the Mexican American people and campaigned against racial discrimination and prejudice of the Americans to them. The Chicano Movement was involved and covered many differen t issues and subject matters, which included the re-establishment of land grants, to the rights of farmers, to improve and develop education, to the political and voting rights as well as the social treatment. We will write a custom essay sample on The Life of Rodolfo Rodolfo Speedy Gonzales or any topic specifically for you Only $17.96 $11.86/page It describes the feelings and the thoughts of the Chicanos and it emphasizes the desire for racial equality and impartiality. It is shown in some of the lines in the poem. I look the same; I feel the same; I cry and sing the same.