2001 Ap Chemistry Response Scoring Guidelines

2001 Ap Chemistry Response Scoring Guidelines 2001 AP Chemistry Response Scoring Guidelines This document outlines the scoring guidelines for the 2001 AP Chemistry exam specifically focusing on the freeresponse questions These guidelines provide a detailed description of the expected content and reasoning necessary for students to earn full credit on each question They also illustrate the various levels of understanding and the specific points awarded for different responses Structure of the Scoring Guidelines The scoring guidelines are structured according to each individual freeresponse question with the following format Question The complete text of the freeresponse question Scoring Rubric A detailed breakdown of the scoring criteria including Points The total number of points awarded for the question Specific scoring points Each point represents a specific aspect of the answer that needs to be addressed correctly Examples Sample student responses and corresponding point values Explanations Detailed explanations of the rationale behind each point and the expected level of understanding General Notes Additional information relevant to the question such as acceptable alternative answers or common student errors Content Covered by the Scoring Guidelines The scoring guidelines cover all aspects of the freeresponse questions including Scientific principles Demonstrating knowledge of key chemical concepts and principles Problemsolving Applying these principles to solve specific problems and interpret data Communication Effectively communicating scientific ideas and reasoning in a clear and concise manner Laboratory skills Demonstrating understanding of experimental techniques and data analysis Use of the Scoring Guidelines 2 These scoring guidelines are intended to be used by teachers students and AP examiners for the following purposes Teaching To provide teachers with a clear understanding of the expectations for the exam and to inform their instruction Learning To help students understand the specific skills and knowledge assessed on the exam Scoring To provide consistent and reliable scoring across different examiners and to ensure fair and accurate assessment of student performance Note This document only provides the general structure and content of the scoring guidelines The specific content of each question and scoring rubric will vary depending on the specific year and exam Example Scoring Guideline for a FreeResponse Question Question A student performs an experiment to determine the enthalpy change for the reaction of hydrochloric acid with sodium hydroxide The student mixes 500 mL of 100 M HCl with 500 mL of 100 M NaOH in a calorimeter The initial temperature of both solutions is 250 C The final temperature of the mixture is 315 C a Calculate the heat absorbed by the solution Assume the specific heat capacity of the solution is 418 JgC and the density of the solution is 100 gmL b Calculate the enthalpy change H for the reaction in kJmol of HCl Scoring Rubric Points 5 a Heat Absorbed 1 point Correct calculation of the mass of the solution 1 point Correct calculation of the temperature change 1 point Correct calculation of the heat absorbed by the solution using the formula q m c T b Enthalpy Change 1 point Correct calculation of the moles of HCl used in the reaction 1 point Correct calculation of the enthalpy change per mole of HCl using the formula H q moles of HCl 3 Examples a Student response Mass of solution 500 mL 500 mL 1000 mL Density 100 gmL so mass 1000 g T 315 C 250 C 65 C q 1000 g 418 JgC 65 C 2717 J Points awarded 3 points b Student response Moles of HCl 00500 L 100 molL 00500 mol H 2717 J 00500 mol 54340 Jmol 543 kJmol Points awarded 2 points Explanations a The student correctly calculates the mass of the solution the temperature change and then uses the appropriate formula to determine the heat absorbed b The student correctly calculates the moles of HCl used in the reaction and then uses the heat absorbed and moles of HCl to determine the enthalpy change per mole General Notes Students should be careful to use the correct units and conversions in their calculations Students should show all their work clearly and organized The enthalpy change for this reaction should be negative indicating an exothermic reaction This example demonstrates the structure and content of a single freeresponse question scoring guideline The same format and level of detail would be used for each of the other freeresponse questions on the 2001 AP Chemistry exam