CHE 105 – Week 7 Formative Assessment. Instructions: • • • • • Each student will work on this assignment alone. Assignments with identical answers will earn grades of zero. If you have questions, you are to ask me, your instructor, not your peers. The assessment will be printed out, completed, scanned, or photographed and uploaded to the upload area. Only assignments uploaded to the class will be graded. You must show ALL work. Submissions with answers only will not be evaluated. Formats: The following formats will be evaluated: • Microsoft Word Note: if you cannot scan your work before submitting, you are welcomed and encouraged to do the following: • • • • Take an image of each page of your work with your phone. Copy/paste those images to a Word document. Make sure the image size is the same as the page. Submit one image per page. Save the file as a Word document. Submitted files in the following formats will NOT be evaluated: • Pages • Lone Jpeg images • Any other file formats *********************************************** The Week 7 Formative Assessment has two parts. The first has to do with the gas laws. The second with the Kinetic Molecular Theory. You will be using th phet simulator found at https://phet.colorado.edu/sims/html/gas-properties/latest/gas-properties_en.html For the second part of Part 1. Part 1: Gas Laws. Adapted from Gas_Properties_Laws 2/22/2024 Loeblein; Sarah Borenstein’s lesson on PhET Teacher’s Activity Database from https://phet.colorado.edu/en/contributions/view/3500 In this unit, you will first predict what you will find, and then – you will use the PhET simulator to confirm your thinking. The Learning Goals of this experiment are: • Design experiments to measure the relationships between pressure, volume, and temperature. Create graphs based on predictions and observations. Make qualitative statements about the relationships between pressure, volume and temperature using molecular models. • • Predictions: Make a chart like the one below. Without using the simulation, sketch what you think the graphs would look like, assuming the properties listed would change. By convention, the intersection of Y and X is zero, and as you move up or to the right, the values are increasing. Note: Be sure to label your x and y axes. Type or write in the boxes and expand as needed. I. Volume-Pressure graph Explain your reasoning for the graph’s appearance II. Volume-Temperature graph Explain your reasoning for the graph’s appearance III. Temperature-Pressure graph Explain your reasoning for the graph’s appearance IV. Number of particles – Volume Explain your reasoning for the graph’s appearance Experiments: 1. For each case, I-IV. Write a short description of how to use the sim to collect data. Then make an Excel spreadsheet for each, graph and curve fit. Some helpful hints – if you set a parameter like temperature constant, then make a change, you may have to watch the temperature adjust and not record your data until the temperature is back to the original setting. These experiments would be difficult in a real situation because it is complicated to isolate parameters like you can in the sim. 2. After you have made your graphs in Excel, check your predictions, and see if any might need some corrections. If necessary, make corrections in a different color including corrections to your reasoning. 3. Complete this table: Relationship Direct or indirect? V vs P V vs T T vs P Moles vs V Constant parameters Whose Law? Briefly, why according to particle model. 4. Using your results, explain each of the following scenarios. Make sure to refer to which graph can be used as evidence for your answer. a. Explain why bicycle tires seem more flat in the winter than in summer. b. Please describe the difference between a ‘direct’ relationship and an indirect relationship of parameters. c. Explain why a can of soda pop explodes if left in the hot sun. d. A rigid container filled with a gas is placed in ice (ex. nalgene bottle). What will happen to the pressure of the gas? What do you think will happen to the volume? Part 2: Kinetic Molecular Theory. (Adapted from ‘Student directions for understanding KMT.docx from https://phet.colorado.edu/en/contributions/view/2816) Learning Goals: Students will be able to describe matter in terms of particle motion. The description should include • • • • Diagrams to support the description. How the particle mass and temperature affect the image. How the size and speed of gas particles relate to everyday objects What are the differences and similarities between solid, liquid and gas particle motion 1. Open Gas Properties and then use the pump to put a little gas into the box. a. Observe gas particles’ behavior. b. Pump in some lighter particles and talk about the similarities and differences that you see between heavy and light particles. c. Use the simulation to see how changing the temperature affects the behavior of the gas particles. d. Write a description (below) for a gas based on your observations; include diagrams to help with your description. 2. How fast do you think the air particles in this room are moving compared to a car going 50 mph (about 22m/s)? Put your answer is in the form, ‘a molecule travels ___ as fast as a car” 3. Using the simulation, test your idea from question 2 and give evidence to support or revise your thoughts. For evidence, include how you used the simulation to collect data, and any calculations. 4. Write a paragraph that explains the differences and similarities between solid, liquid and gas particle motion; include drawings to help with your explanations.