LS2_a - Unit 1 How do we analyze a system Searching for...

Info icon This preview shows pages 1–10. Sign up to view the full content.

View Full Document Right Arrow Icon
Chemistry XXI Unit 1 How do we analyze a system? Searching for Differences
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Chemistry XXI Lab Session 2 How do we identify an unknown substance?
Image of page 2
Chemistry XXI Chemical thinking and practices are very useful in determining the identity and analyzing the properties of chemical substances. Detection: Does the sample contain substance X? Identification: What is the identity of the substance in this sample? Central Goals and Questions Separation: How can the substances present in the sample be separated? Quantitation: How much of substance X is in the sample? The Motives These are the types of questions we want to answer.
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Chemistry XXI Imagine that you are employed by a recycling firm. You have been assigned to devise a quick and cheap method for identifying different types of plastics. The Challenge What beginning questions do you need to answer to complete your job? Given these unknown samples of plastics:
Image of page 4
Chemistry XXI Beginning Questions Examples: Are all of the samples the same type of plastic? What is the identity of each plastic? What properties can be measured to distinguish one type of plastic from another? How do we best measure these properties (accuracy and precision)? What resources do I have to complete the task?
Image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Chemistry XXI The Resources Pure samples of known plastics. Balances (TC 4). Vernier calipers. Glassware. These are the resources you have available to complete your task:
Image of page 6
Chemistry XXI Initial Decisions Given the resources available, discuss in your groups how you propose to answer the central question for this lab: What is the identity of the unknown plastics? What differentiating characteristic would you use? What will you measure? How will you measure it? What would you do with these measurements? How will you stay safe?
Image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Chemistry XXI Trial Tests Let′s explore! As a class, decide which groups will be determining the value of the property that differentiates the different reference plastics. What should each group do? How can you ensure reproducibility of measurements? How can you determine what technique is best? You have 30 minutes Available resources: Pure samples of known plastics. Balances (TC 4). Vernier calipers. Glassware.
Image of page 8
Chemistry XXI The tools you use needs to measure the property that you want (length, volume, etc.) The tools need to measure in the range you need ( accuracy ).
Image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 10
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern