Chromotography

In: Science

Submitted By kesar
Words 1387
Pages 6
Chlorophyll Chromatography

Subject Area: Chemistry
Grade Level: Middle School Chemistry
Lesson Title: Chlorophyll Chromatography

National Science Education Standards:

Science as Inquiry: 5–8

• Properties and Changes of Properties: 5–8

Suggested Prior Knowledge: concepts of solutions, mixtures, separation of mixtures, solubility
Purpose: To give students an understanding of paper chromatography and to allow students to separate a mixture of pigments extracted from leaves.

Key Vocabulary:

absorbent—material used in chromatography that will attract and absorb the compounds being separated chlorophyll—one of many pigments used by plants to absorb energy from sunlight in the process of photosynthesis chromatography—method used to separate a mixture of compounds based on differing solubilities of the compounds in the solvent being used eluent (solvent)—material used in chromatography which carries the compounds to be separated through the absorbent photosynthesis—process by which plants convert energy from sunlight, water, and carbon dioxide gas into sugar solute—substance dissolved in a solution solution—homogeneous mixture of two or more substances solvent—substance dissolving the solute in a solution

Objectives:

1. Students will be able to design and carry out an investigation to separate the pigments from a leaf by paper chromatography. 2. Students will identify a mixture by separating it into different compounds.

Materials:

- safety goggles
- chromatography paper or filter paper cut into strips
- chromatography solvent (commercially available: 90% petroleum ether and 10% acetone or 50/50 mixture of acetone and water)
- isopropyl alcohol, acetone, water and/or ethanol (optional additional solvents)
- pencil
- ruler
- wooden splint
- 250 ml Erlenmeyer flasks
- 50 ml…...

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