Name Date Period ID# Identification of Substances by Physical and Chemical Properties Lab Activity

Transcription

1 Name Date Period ID# Identification of Substances by Physical and Chemical Properties Lab Activity Standards: PS1(9-11) INQ1, PS1(1a), ESS1 (9-11) SAE+POC-3, ESS1 (3d) Essential Questions: -How should data be collected and used to distinguish between different substances with similar physical properties? -How can evidence be used to identify a substance? -How can our understanding of chemical processes be used to explain why the earth s crust has changed over time? Objective: In this lab activity you will be testing some unknown substances. You will identify these substances based on their characteristic physical and chemical properties using a chart of actual lab data. You will then apply this knowledge in order to explain how to the earth s crust is constantly undergoing chemical changes over time. Materials: Unknown substances Acetic Acid Hydrochloric Acid Silver Nitrate Matches Candle Ring Stand and Ring Can lid well tray Water bottle sticks pipettes Toothpicks magnet goggles/apron Procedure: Part 1: Physical Properties: a) COLOR: Record the colors of the unknown substances in your data table b) MAGNETISM: Place a small out of each substance into the well plate. Run a magnet under the unknown substances to determine if the substance is magnetic. Record in your table. c) REALTIVE SOLUBILITY: Using the water bottle, squirt a small amount of water into the substance in order to see if it dissolves. Use a toothpick or stick to stir each of the substances. Record in your table. d) MELTING POINT: Set up a ring stand with a ring and foil over the ring. Using a stick, place a small amount of each unknown onto a piece of foil. It may be helpful to make a drawing of the lid and where you placed each unknown. Put a candle directly under the lid and light with matches. Wait 5 minutes and record if the substance melted or not in your data table. Allow the lid to cool and wipe the contents into a paper towel and discard into trash. Part 2: Chemical Properties: In a clean and dry well plate, place 3 small amounts of each unknown substance. It may be helpful to make a drawing of the tray and where you placed each unknown. Using a pipette drop 5 drops of hydrochloric acid into each of the first wells. Observe each well and note if each substance reacts with the acid. Some may react quickly, slowly, some not at all. Record all observations. Repeat using acetic acid, and then again with the silver nitrate. Clean your well tray by dumping the contents into a paper towel and was and dray the tray.

2 Substances Color Magnetism Relative Solubility Unknown 1 Melting with HCL with Acetic Acid with Silver Nitrate IDENTITY: Unknown 2 Unknown 3 Unknown 4 Unknown 5 Unknown 6 Unknown 7

3 Lab Report for Identification of Substances by Physical and Chemical Properties Instructions The purpose of the lab report is to demonstrate that each individual student can explain the purpose, results, and conclusions in their own words. Although I am only asking you to complete the introduction and results/discussion section of the lab report this time, it is good practice to format your lab report properly as shown below: Heading: Name Date Chemistry Period Title of Lab *Introduction/Purpose: [This is in paragraph form!] In this section you will describe, in detail, the scientific principles being investigated through the experiment. Pretend you are explaining these scientific ideas to an elementary student. Begin by approaching the topic in general terms and then break it down into specifics. Be sure to define and discuss any relevant terms and scientific theories. Background knowledge to be included in this lab report: What was the purpose of the lab? Answer the questions on the lab: o How should data be collected and used to distinguish between different substances with similar physical properties? o How can evidence be used to identify a substance? What is a physical property? What is a chemical property? How are physical and chemical changes different? What are some examples of physical and chemical properties/changes that illustrate these differences? What is a chemical reaction? Materials: - Don t worry about this section this time! Procedure: - Don t worry about this section this time! Data/Calculations: - Don t worry about this section this time! *Results/Discussion: [This section is also in paragraph form!] Your goal here is to discuss the outcome/results of your lab. DO NOT simply restate all of your data. DO NOT restate all the details to your procedure. Instead, explain what your data tells you and draw some generalizations regarding what you saw happening in the lab. Also answer the following question in complete sentences How did the lab demonstrate the principles that were being investigated? (see the checklist below) THIS IS YOUR CHANCE TO SHOW ME WHAT YOU LEARNED DURING THE EXPERIMENT! Impress me with your chemical knowledge!

4 In your results/discussion for this lab be sure to: Briefly summarize your results using claims and evidence (use data from the activity to support your statements) Identify if your initial predictions of the unknown substances were correct Discuss any errors/mistakes you or your group made. Did these affect your results? SO WHAT?- Relate information from this lab to real world concepts. o For this lab in particular you need to answer the third question and apply your knowledge in order to explain how the earth s crust is constantly undergoing chemical changes over time. The earth s crust is composed mostly of iron (32.1%), oxygen (30.1%), silicon (15.1%), magnesium (13.9%), sulfur (2.9%), nickel (1.8%), calcium (1.5%), and aluminum (1.4%); with the remaining 1.2% consisting of trace amounts of other elements. Using data collected during this activity explain how these elements would be changed over time if the crust is constantly being exposed to chemical processes such as acid rain or other chemical agents. Make sure you cite evidence from the activity to explain this.) Discuss any questions you still have and might want to experiment on further Additional Notes: Although you worked as a team to participate and complete the lab packet, the lab report is done individually. You must do YOUR OWN THINKING and your teammate(s) should NOT have the same report. Reports will be graded largely on their ability to clearly communicate results and important conclusions to the reader. You must, of course, use proper English and spelling, along with comprehensible logic and appropriate style. You should proofread your report as well as spell-check it. Neatness and organization will also influence the grade a report receives. Be sure to follow explicitly the format indicated above. Staple the lab to your report. Avoid being overly verbose and flowery when attempting to convey your point - be concise. Avoid qualitative phrases such as "the results were quite close" or "heat fluxes were in good agreement with the correlation." Be as quantitative as possible. Do not copy material without citing the source.

5 Rubric Trait Exceeding Meeting Approaching Developing Beginning Essential Understanding of Content/ Vocabulary -Clearly demonstrates -Provides strong, credible support of the topic and shares insights that go beyond the obvious and predictable - Demonstrates understanding of related to content by using specific details and/or examples -Demonstrates -Supporting details and ideas may at times be too general -Demonstrates a basic understanding of related to content -Demonstrates understanding but a few minor mistakes are present -Supporting details and ideas may at times be too general AND some incorrect information is included -Uses some content but there are some minor errors -An attempt was made to address the main idea, but the are not clear -Attempts are made to support ideas but may be irrelevant -Attempts to use content words but does not apply them appropriately. -Ideas are unclear and lack a central link to -Words are limited, monotonous, or misused. Participation and Completion of lab packet- 50 pts AND Lab Report Purpose/Results/Conclusion section-50pts