Chemistry End of Year Cornerstone Assessment The Cornerstone Assessments were developed with support through the VDOE Mathematics and Science Partnership Grant Program NCLB Title II, Part B program by high school teachers as a part of the Old Dominion University Learning Enhanced through the Nature of Science (LENS) project. 2012 2013 This assessment consists of two parts. DIRECTIONS to provide to read to students: Today you will be taking the Chemistry End of Year Cornerstone Assessment to find out your skills in scientific investigation, data analysis and interpretation, and scientific reasoning. Read each question carefully and provide your best answer or response. Record your answers directly on the spaces provided in the assessment. Be sure your work and responses are legible. Chemistry End of Year Cornerstone Assessment Version 1 1
Chemistry Baseline Cornerstone Assessment: Part A. Experimental Design Directions: Read the paragraph below and then respond to the questions. Baking soda and vinegar react to form carbon dioxide gas. Patty s little brother is making a science fair volcano for a project, and he wants to create a big explosion. The volcano is designed to hold 10 milliliters of vinegar. Patty offers to help her brother set up an experiment to determine how much baking soda, when reacted with the 10 milliliters of vinegar, will release the most carbon dioxide. Patty obtains 100 milliliters of vinegar, 25 grams of baking soda, 5 plastic bottles, 5 balloons, a spool of string, and a meter stick. 1. What should be the independent variable in Patty s experiment? Explain your choice. 2. What should be the dependent variable in Patty s experiment? Explain your choice. 3. State an appropriate hypothesis for Patty to test. Explain your hypothesis. 4. Are there conditions that should remain constant in this experiment? Explain your answer, and give examples, if necessary. 5. A well designed experiment must have a control for comparison purposes. Identify an appropriate control for this experiment. Justify your answer. Chemistry End of Year Cornerstone Assessment Version 1 2
6. Design a procedure for Patty to carry out to determine the effect of varying the amount of baking soda added to the amount of gas produced. List the steps below and the materials needed. 7. Create a data table that can hold all the data you would gather through your procedure. Chemistry End of Year Cornerstone Assessment Version 1 3
Chemistry Baseline Cornerstone Assessment: Part B. Data Interpretation and Analysis and Scientific Reasoning Directions: Read the paragraph below and review the data table. Then, answer the questions that follow. Patty carries out an experiment by setting up five plastic bottles. To each plastic bottle, she adds 10 milliliters of vinegar. She then measures out the following amounts of baking soda: 1.0 g, 2.0 g, 3.0 g, 4.0 g, 5.0 g. She pours each amount of baking soda into a different balloon and fastens the balloons over the openings of each of the plastic bottles. To initiate each reaction, she pours the baking soda out of the balloon and into the bottle. As the reactions proceed, carbon dioxide is released and fills the balloons. A picture of the setup is shown below. Once each balloon stops inflating, Patty uses a string to measure the circumference of the balloon around the widest part, and then Patty measures the length of the string that stretched around the balloon. Patty records her data in the table below. Circumference of balloon Bottle # Amount of vinegar Amount of baking after reaction (ml) soda (g) (cm) 1 10. 1.0 15.3 2 10. 2.0 21.5 3 10. 3.0 26.2 4 10. 4.0 31.8 5 10. 5.0 31.9 1. Calculate the number of moles of baking soda that were added in the first trial. The chemical formula of baking soda is NaHCO3 (1 mol = 84 g). Chemistry End of Year Cornerstone Assessment Version 1 4
2. Create a graph showing the relationship between the amount of baking soda added and the circumference of the each balloon. Graph the data on the grid below. Be sure to label and correctly scale the axes and give the graph a title. 3. What can you interpret from the data? Specifically, relate how the amount of baking soda affects the amount of gas released. Explain your answer using the data. 4. Suppose Patty set up a sixth trial with 10 milliliters of vinegar and 6.0 grams of baking soda. Give an appropriate prediction of the circumference of the balloon for that trial. Explain your answer using the data. 5. Patty hypothesized that increasing the amount baking soda in the reaction would produce more carbon dioxide. Based on this experiment, do you accept or reject her hypothesis? Explain your decision. Chemistry End of Year Cornerstone Assessment Version 1 5
6. When Patty completed her experiment, she realized that the bottle for the first trial was smaller than the other four bottles. How would this affect her measurement for trial #1? Explain your answer. Chemistry End of Year Cornerstone Assessment Version 1 6