Project 1 Guide - LAB 1 overview PDF

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LAB 1 overview...

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Chemical Thinking

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Project 1

Chemical Analysis I: Separating Components Some pigments used to color a variety of materials are of mineral origin. Other types of pigments, called lake pigments, are prepared by precipitating organic dyes (substances mostly composed of carbon, hydrogen, oxygen and nitrogen) onto an inert binder (a substance that holds the pigments together in a paint). For thousands of years, lake pigments have found use in decoration and the arts. Red lakes were particularly important in Renaissance and Baroque paintings; they were often used as translucent glazes to portray the colors of rich fabrics and draperies. Presently, lake pigments find extensive use in cosmetics and solid foods. In this project you will separate the different components of a lake pigment. For this purpose, you will have to first identify differentiating characteristics of each component that can be used to separate it from the others. You are expected to optimize your separation process to minimize a) the number of steps required to accomplish the separation, b) the amount of resources used and c) the amount of waste generated during the process.

Organic dye (on surface of inert binder)

Green Lake Pigment (greatly magnified below)

P1-1 Background Lake Pigment Materials in our surroundings, both natural and synthetic, tend to be mixtures of diverse substances. The air (particles of inert Inert binder you breathe, the food you eat, the water you drink and the clothes you wear are comprised of tens or binder coated with (core of lake organic dye) pigment) hundreds of different substances. Chemical scientists and engineers have developed a variety of strategies to separate these components for different purposes. For example, we have learned to extract dyes from flowers, scents from fruits, caffeine from coffee and fat from milk. All separation strategies are based on the identification of a distinctive property of the substance of interest (a differentiating characteristic) that can be used to isolate it from others. Different separation techniques take advantage of specific differentiating characteristics: for example, distillation (boiling point), liquid-liquid or liquid-solid extraction (solubility) and centrifugation (density).

All separation methods require investment of time, material resources, and energy. Many separation processes produce waste that need to be properly disposed of to reduce negative environmental effects and health risks. In recent years, there has been an effort to follow "greener" laboratory strategies following basic principles, such as:    

Methods should be designed to use and generate substances that possess little or no toxicity to human health and the environment It is better to prevent waste than to treat or clean up waste after it has been created Energy requirements should be recognized for their environmental and economic impacts and should be minimized Substances used in a chemical process should be chosen to minimize the potential for chemical accidents

Chemical Thinking

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Project 1

P1-2 Your Challenge You will have two lab sessions to complete this project. You are expected to use your time to address the challenge by carrying out experiments that allow you to complete the following tasks:

TESTING

SEPARATION

Task 1: Design a strategy to systematically test the solubility of known components of a lake pigment in different liquids to identify differentiating characteristics that can be used to separate them.

Task 2: Design and test a strategy to separate each component of a lake pigment.

Preparatory Work Review the video (click on title to launch)  Qualitative Testing. Summarize in your own writing the core goal(s) of the project. Write an initial plan to identify useful differentiating characteristics of the targeted components.

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Preparatory Work 

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Review videos for relevant separation techniques (click on title to launch)  Mixture Separation Technical Guide,  Hirsch Funnel Filtration Technical Guide,  Centrifugation Technical Guide. Write an initial plan to separate the components of the lake pigment.

OPTIMIZATION Task 3: Optimize the designed separation strategy to minimize the number of steps needed to separate all components of the lake pigment, and minimize material and energy resources and waste.

Preparatory Work 

Analyze collected data to identify and propose potential optimization strategies.

Time management will be important in your efforts to successfully separate the different components of the lake pigment and optimize your separation strategy. Please consider that during each session of this project you are expected to have time to share and discuss your results with your lab classmates, and in the final session, to write a technical communication summarizing your major findings and their implications. You will have access to the following resources to address the challenge (nevertheless, not all of them may find use in meeting your goals):     

Sample of the targeted lake pigment (a solid) Samples of individual components of the lake pigment (inert binder and concentrated solutions of red dye, orange dye and blue dye) Different types of liquid substances [Cyclohexane, NANOpure™ water, acidic water (1 M HCl), alkaline water (1 M NaOH)] 1-dram testing vials with caps (on the reagent bench) Clay Adams® Brand Compact II centrifuge (in the first hood)

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Hirsch filtration set-up (check out item) 1 cm filter paper (on the reagent bench) Support rod/support arm (attached to the islands) 2-prong clamp (located in a labeled drawer under the reagent bench) Vacuum hose (located in a labeled back-bench drawer) Equipment in your locker (see the locker inventory on D2L)...