The student earned 6 points: 2 points in part (a), 1 point in part (b), 3 points in part (c), and no points in part (d). In part (a) the student presents a solution curve through the point ( 0, 8 and a solution curve through the point ) ( 3, 2 . ) Both curves presented have the general form required relative to the slope field, and the student earned both points. In part (b) the student earned the first point for correctly demonstrating two steps of Euler’s method using the initial value f ( ) 0 = 8 and a step size of 1
Then the student pours 25 mL of the 6 M HNO 3 into a beaker and adds a 0.6489 g sample of the alloy. After the sample completely reacts with the acid, some saturated NaCl( aq ) is added to the beaker, resulting in the formation of an AgCl precipitate. Additional NaCl( aq ) is added until no more precipitate is observed to form. The precipitate is filtered, washed, dried, and weighed to constant mass in a filter crucible. The data are shown in the table below.
in which x and y are usually small whole numbers. In this expression, called a rate law, [A] and [B] represent, respectively, the concentration of substances A and B, and k is called the rate constant, that is specific for the reaction. The exponents x and y are called the orders of the reaction with respect to the concentrations of substances A and B respectively. For example, is x=1, the reaction is said to be first order with respect to the concentration of A. If y=2, the reaction would be second order with respect to the concentration of B. The so-called overall order of the reaction is represented by the sum of the individual orders of reaction. For examples just mentioned, the reaction would have overall order of:
Extensive password requirements can overload human memory capabilities as the number of passwords and their complexity level increases. The exponential growth in security incidents (Carnegie Mellon Computer Emergency Response Team, 2004) requires a comprehensive ap- proach to the development of password guidelines which do not exceed human memory limita- tions yet maintain strength of passwords as necessitated by the information technology (IT) community. The IT community consists of network administrators or security officers who are directly responsible for information security in terms of integrity, confidentiality, and availability of information. In earlier investigations, over 50% of incidents that occur within government and private organizations have been connected to human errors (NIST, 1992). The impact of human error on information security is an important issue that left unresolved can have adverse affects on industry. This research is focused on measuring the impact of password demands as a means of authentication and mitigating the risks that result when these demands exceed human capabili- ties.
There are many measures that can calculate the topical similarities between two summaries. For evaluation the results we use two methods. The first one is by precision (P), recall (R) and F1-measure which are widely used in Information Retrieval. For each document, the manually extracted sentences are considered as the reference summary (denoted by Summ_ref). In this approach the candidate summary (denoted by Summ_cand)is compared with the reference summary. The formulas for the measures P, R and F1 are as follows.Depending on what the summarization program focuses to make the summary of the text, summaries can be generic or query relevant. This paper mainly focused on query specific extractive summarization of source document. In extractive summarization each sentence in a document is scored based on some scoring method with respect to the query. The final outcome contains the most important sentences in the document related to the query without redundancy which is known as summary of the document. For single document order of sentence in the original document can be used as order to generate summaries.
The illustration on the right shows two covalent network solids, diamond(a) and graphite(b). With regards to intermolecular forces (attractions) and intramolecular forces (bonds), which is a harder solid, diamond or graphite? How is that illustrated in the model to the right?
Concept: The polarity of water molecules results in hydrogen bonding a. The structure of water is the key to its special properties. Water is made up of one atom of oxygen and two atoms of hydrogen, bonded to form a molecule. b. Water molecules are polar. The end bearing the oxygen atom has a slightly negative charge, whereas the end bearing the hydrogen atoms has a slightly positive charge.
I merely throw out these sentiments for the purpose of showing you that South Carolina, having declared her purpose to be this, to make an experiment whether, by a course of legislation, in a conventional form, or legislative form of enactment, she can defeat the execution of certain laws of the United States, I for one, will express my opinion that I believe it is utterly impracticable, whatever course of legislation she may choose to adopt, for her to succeed. . . . I say it is impossible that South Carolina ever desired for a moment to become a separate and independent state.
The results obtained by this heat/work ACS activity display greater increases in student knowledge gains than the results of traditional teaching in previous years, as reported by the chemistry teacher. Later in the year, the teacher asked the Fellow to exemplify dynamic equi- librium with ACS, and reflected that the results were comparable to the heat/work activity. As with energy/heat/work, since students cannot easily see dynamic equilibrium happening in a chemical reaction, a concrete, practical example from daily life could develop the students’ understanding of the concept. The Fellow utilized an activity that could be used in classes such as biology or chemistry to emphasize the role of molecules in diffusion.
Pre-APChemistry is a study of the properties of matter and the changes that matter undergoes. Students will study questions as listed in Objective Notes/Essential Questions. Level of Expectation . Chemistry Handbook practice problems, p. This PDF book incorporate matter chemistry pre ap practice tests information. To download free pre-ap chemistry.pdf hazelwood school district you need to register.
Then the student pours 25 mL of the 6 M HNO 3 into a beaker and adds a 0.6489 g sample of the alloy. After the sample completely reacts with the acid, some saturated NaCl(aq) is added to the beaker, resulting in the formation of an AgCl precipitate. Additional NaCl(aq) is added until no more precipitate is observed to form. The precipitate is filtered, washed, dried, and weighed to constant mass in a filter crucible. The data are shown in the table below.
● When elements are burned, electrons in the element are excited and jump to the next energy level in the atom. As the return to ground state, the electron releases the energy gained in the form on a photon that has a certain frequency. The difference of energy levels is unique to the element.