Total energy evolved when all the atoms return to ground state. Calculate total energy evolved when all the ions return to the ground state. Calculate angular momentum of e.
Clarifications of the IA criteria Design Aspect 1: This should ensure that a range of plans will be formulated by students and that there is sufficient scope to identify both independent and controlled variables. Although the general aim of the investigation may be given by the teacher, students must identify a focused problem or specific research question.
Commonly, students will do this by modifying the general aim provided and indicating the variable s chosen for investigation. The teacher may suggest the general research question only.
Asking students to investigate some property of a reaction system such as esterification, where no variables are given, would be an acceptable teacher prompt. This could then be focused by the student as follows: Alternatively, the teacher may suggest the general research question and specify the dependent variable or a quantity derived from the dependent variable.
An example of such a teacher prompt would be to ask the student to investigate factors influencing retention in thin-layer chromatography. It is not sufficient for the student merely to restate the research question provided by the teacher. Independent variables are those that are manipulated, and the result of this manipulation leads to the measurement of the dependent variable.
A controlled variable is one that should be held constant so as not to obscure the effect of the independent variable on the dependent variable.
The variables need to be explicitly identified by the student as the dependent measuredindependent manipulated and controlled variables constants. Relevant variables are those that can reasonably be expected to affect the outcome.
The relevant controlled variables are temperature and the initial concentrations in the reaction mixture of ethanol and ethanoic acid. The student should not be penalized for identifying further control variables that may not be so immediately relevant.
Students should not be: The method should include explicit reference to how the control of variables is achieved. If the control of variables is not practically possible, some effort should be made to monitor the variable s.
A standard measurement technique may be used as part of a wider investigation but it should not be the focus of that investigation. Students should be assessed on their individual design of the wider investigation.
If a standard measurement technique is used it should be referenced. For example, while planning an investigation to study the factors that influence the rate of oxidation of vitamin C in fruit juices, the student may have adapted a method for vitamin C determination from a literature source.
A standard reference would then be expected as a footnote. Students should not be told: The planned investigation should anticipate the collection of sufficient data so that the aim or research question can be suitably addressed and an evaluation of the reliability of the data can be made.
Example considerations when assessing sufficiency of data could be the following: If a trend line is to be plotted though a scattergraph then at least five data points are needed, so the plan should allow for repeated measurements to calculate a mean for example, repeat calorimetric determinations when investigating an enthalpy of reaction.
The plan should show an appreciation of the need for a trial run and repeats until consistent results are obtained in titrimetric determinations. Data collection and processing Ideally, students should work on their own when collecting data. When data collection is carried out in groups, the actual recording and processing of data should be independently undertaken if this criterion is to be assessed.
Recording class or group data is only appropriate if the data-sharing method does not suggest a presentation format for the students. This may include associated qualitative data. It is permissible to convert handwritten raw data into word-processed form.
Associated qualitative data are considered to be those observations that would enhance the interpretation of results. For example, when students say there is an uncertainty in a stopwatch measurement because of reaction time, they must estimate the magnitude of the uncertainty.
Within tables of quantitative data, columns should be clearly annotated with a heading, units and an indication of the uncertainty of measurement. The uncertainty need not be the same as the manufacturer's stated precision of the measuring device used.May 01, · One of the reactions involved a high temperature reaction between carbon tetrachloride and the oxide to form carbon dioxide and the corresponding metal chloride.
A similar high temperature reaction was conducted between the metal oxide and hydrogen sulfide to form water and the corresponding metal sulfide. Q Write a balanced equation for the hydrolytic reaction of PCI 5 in heavy water. Ans.
All the bonds that are present in PCI 5 are not similar. It has three equatorial and two axial bonds. The equatorial bonds are stronger are stronger than the axial ones. Therefore, when PCI 5 is heated strongly, it decomposes to form PCI 3.
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Studyres contains millions of educational documents, questions and answers, notes about the course, tutoring questions, cards and course recommendations that will help you learn and learn. Titration in the presence offluoride ion consumed ml ofKMn04 that was N against oxalate.
write a balanced chemical equation for the reaction, assuming that the complex is MnF4~. what was the % of Mn in the sample? Write the reaction of PCl5 with heavy water. Write a balanced chemical equation for the reaction showing catalytic oxidation of NH3 by atmospheric oxygen.
Give chemical reaction in support of the statement that all the bonds in PCl5 molecule are not equivalent. By giving a balanced equation show how B(OH)₃ behaves as an acid in water.