Whitney Young High School

ARISE CHEMISTRY

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Syllabus - Spectronic 20 Project - Teacher's Reflections - Parents Comments

 

Syllabus

Introduction (3 days)

Lab safety, Scientific method

Matter (1 week)

Classification of matter, physical and chemical properties and changes, separation of mixtures

Measurement (2 weeks)

Mass, volume and density, scientific notation, significant figures, error analysis, graphing skills

Chemical formulas (1-2 weeks)

Introduction to atomic structure and ions, writing formulas, inorganic and organic nomenclature

Mole (1 week)

Mole concept, mole conversions, molar mass

Composition of compounds (1 week)

Percent composition, empirical formula, molecular formula

Chemical reactions (2 weeks)

Types of reactions, balancing equations

Stoichiometry (2 weeks)

Conversions: mole-mole, mole-mass, mass-mass; limiting reactant

 

Gas laws (3 weeks)

Properties of gases, Boyle's-Charles'-Gay-Lussac's laws, Ideal gas law, molar volume, gas stoichiometry

Atomic structure (3 weeks)

History of the atom, composition of the atom, electromagnetic spectrum, intro to spectrophotometry, electron configuration

Periodic table (2 weeks)

Ion formation, activity series, periodic trends

Bonding (2 weeks)

Ionic bonding, covalent bonding, Lewis structures, bond polarity, molecular geometry

Solutions (3 weeks)

Liquids and solids, water, solution concentration, colligative properties, ionic equations

Thermochemistry (2 weeks)

Energy requirements for the changes of state, calorimetry, thermochemical equations (Hess' law)

Kinetics (1 week)

Factors that affect rates of reactions, energy diagrams

Equilibrium (2 weeks)

Equilibrium constant, solubility product constant, Le Chatelier's principle

Acids and bases (2 weeks)

Nomenclature, definitions, pH calculation, neutralization, titration, salt hydrolysis, buffers

Oxidation-reduction (2 weeks)

Oxidation numbers, half-reaction method, electrochemistry

Organic and Biochemistry (2 weeks)

Isomers, functional groups, polymerization, aminoacids, peptides, proteins, enzymes, nucleic acids

 

Spectronic 20 Project

Overview of unit: The students are introduced to spectrophotometry during the study of atomic structure. It helps them to understand the relationship between the wavelength and the color of the visible spectrum. They learn how to use spectrophotometer, an essential instrument of any contemporary chemistry lab. The students learn for the first time how to prepare solutions of various concentrations (we study that in the next unit), they practice standard curve construct�ion and graphing skills.

Lesson plan: This project was designed to assess how well the students - know spectrophotometer (technology),

-Understand the relationship between the color of the solution and the wavelength of the visible radiation absorbed/transmitted (atomic structure link, integration - art classes color wheel),

- Can plan and conduct an experiment on their own (engagement),

- Use standard curve to determine concentration of unknown (integration).

The students are given two lab �days to work on their experiment. They have to determine the concentration of two unknown solutions of a certain color using Spec-20 instrument, standard solution of that color with a known concentration, quartz cuvettes for dilutions, graph paper.

The teacher using food coloring prepares several unknowns and standard solutions. The students are aware that the project is independent work - they shouldn't expect help unless their instrument is not working, then the teacher changes light bulb, etc. The students can consult their notes and previous labs with the Spec-20 to design appropriate procedure for the experiment.

This project assesses so many different areas that it is assigned a value of a test. 10% of that grade is the accuracy of the unknown that doesn’t fit on the standard curve constructed determination of, which is very challenging for students (they’ve never done it before). Grading rubric is included on the handout

 

Teacher's Reflections

During the introduction to spectrophotometry I discovered that the students were familiar with the complimentary color concept not only because they heard about it in physics, but also because some art teachers were using color wheel at that time, so some students were bringing their color wheels constructed in art classes to chemistry lab to help with the wavelength determination.

All students were on task during the two allotted lab periods, although some of them were frustrated by the difficulty of the assignment and my refusal to lead them by hand. These frustrated ones were not attentive enough during previous introductory labs with the instrument, and although they finally figured out how to set up the experiment, their data turned out to be inaccurate, because it was obtained in a sloppy way at the last moment of the two lab periods.

Most of the Spec-20s worked well (we have five instruments at school, and we borrow the rest from Chicago Van Program sponsored by Chicago State University). It would be helpful if we had a classroom set of spectrophotometers, but they cost about thousand dollars each, so their acquisition has to be spread over a long period of time. Having a classroom set of Spec-20s in our school will also help Ms.Brice (Arise Biology teacher) in her Biotechnology class.

Most of Arise Chemistry students were successful in this experiment because:

-They showed more confidence approaching challenging tasks all year due to their physics lab experiences (a lot of activities in physics are very challenging)

- They did demonstrate better lab skills (ability to work as a group, ability to plan and perform experiments in a given timeframe, their graphing skills were just superb)

- They were familiar with the concept of calibration while other students had to have additional explanation (majority of them never encountered it before).

Therefore Arise students, usually achieving at 4-8% lower than other classes were only 3% below other honors classes on this project. (Which was the case for lab results almost all year, although they were not as good at turning in their homework, and, therefore, their test scores were usually lower).

 

Parents’ Comments

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Last Update: August, 24 2000
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