day 2 - gc learning activity

8/7/2019 Day 2 - GC Learning Activity

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Day 2 - Learning Activity Lesson PlanKleier ± Chemistry 3 (Special Topics)

Gas Chromatography as an Identification Method

Objective: Students will be able to identify an unknown substance using a Gas Chromatograph,accessing calibration curves using relevant spectrographic databases and comparingexperimental results against accepted values.

NJ Science Standards

y

NJ 5.1.12A3: use Scientific principles and theories tobuild and refine standards for data collection, posingcontrols, and presenting evidence

y

NJ 5.1.12D.2: Represent ideas using literalrepresentations, such as graphs, tables, journals,concept maps, and diagrams.

y

NJ 5.2.8A.5: Identify unknown substances based ondata regarding their physical and chemical properties

y

NJ 5.2.12.A5: Describe the process by which solutesdissolve in solvents.

y

NJ 5.2.6.B1: Compare the properties of reactants withthe properties of the products when two or moresubstances are combined and react chemically.

y

NJ 5.2.P.B.1: Explore changes in liquids and solidswhen substances are combined, heated, or cooled

y

NJ 5.2.12.B.3: Balance chemical equations by applying

the law of conservation of mass.

Materials: GC Instrument (4x), Groups of 5, samples of pure liquids (acetone, 2-Butanone, 2-hexanone, 4-methyle-2-pentanone, 2-pentanone), 3 vials of unknown 3 component mixtures, Lab Worksheet

E ssential Question:

*Do N ow Activity: How do the unique chemical properties of a substance allow theidentification of a compound within a mixture? (answered on index card)

*Exit Question: (same index card) ± same question however specific to GC and

identification of the specific chemical property. Include one additional experimental methodwhich uses a similar chemical property.

Learning Activity & Instructional Method

Students will engage in independent learning facilitated through an initial guided activity.Student will be responsible for the development of calibration curves, comparison to acceptedcurves based from teacher results and averaged against accepted value data.

Performance Task

Students will utilize the worksheet ³Using a Gas Chromatograph: Identifying UnknownCompounds. (See attached, ref: Vernier Website, http://www2.vernier.com/sample_labs/GC-MINI-01-Using_a_GC.doc accessed 3/7/2011 )

Students must have completed pre-lab write-up in lab notebook and receive check on pre-labexercise with discussion of hypothesis to be included in formal report.

Students will share experimental data in order to develop class results section.



F ormative Assessment

Do N ow Activity(D N A) will provide one of the formative assessment opportunity throughinformal discussion of student answers. Second opportunity will be informal discussion duringhomework check on pre-lab exercise and the formal assessment of understanding based on

answers. There will be an additional opportunity during group discussion of pre-lab results anddemonstration of a two phase mixture with liquids of known boiling points (water/alcohol).Students will turn in index cards as a participation grade and evaluation of student understandingand ability to continue to next task. The final formative assessment is the worksheet which willbe completed as a homework assignment, reflected the next day through class discussion andfinally modified through the final formal report.

Homework:

Complete Post Lab worksheet. Begin Formal Report which will include the sequence of GC-

Identifying Mixtures, Quantifying Mixtures, and Verification of Esterification. See GasChromatography Formal lab Expectations handed out last week for the Formal Report GradingRubric.

***E nd of Lesson ***



Reflection:

Lab activity directly correlates with desired results by addressing students learning in the areas of spectrographic analysis, substance identification and experimental procedures. These desiredresults are expressed in the areas of student knowledge, ability and as the topic for essential

questions.

This lesson identifies and drives home one of the essential questions of chemical properties andtheir use for substance identification. The students are asked to reflect on this based on their current knowledge and then asked to evaluate how knowledge changed by the end of the labsession. This lesson addresses the second bulleted essential question through the use as a D N Aand as an Exit Card. The student will also exhibit the knowledge of analytical techniques andchemical databases by execution of a GC lab series of which this activity is one.

WHERET O E lements that are Addressed:

(W): Help the students know Where the Unit is going and What is expected, Help the teacher Know Where the students are coming from. This aspect is covered because this document andthe associated documents(expectations and other lab activities not included in assignment)provide students a framework and places the assignment in context to the larger objective. Itallows the teacher to make on the spot changes to the lesson by informal evaluation of the donow and the pre-lab assignment.

(H) The hook is the essential question which draws them into the lesson and lays the foundationon which the lab activity builds upon and holds their interest throughout the lesson. They areactively involved in the learning experience through the guided practice opportunity.

(E) Students are equipped to explore the concept and apply knowledge to answering specificquestions. They are provided the means to find success and link analytical techniques with their overall objective to develop biodiesel. The lab series, although not fully explored in this specificactivity allows them to connect the various aspects of instrumental analysis with substanceidentification and verification in an authentic manner.

(R) The use of the do now/exit card strategy allows students to develop an idea, practice with thetheory and then revise the idea and reflect on the change in their understanding.

day 2 - gc learning activity

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