Concentration

Summary

Students will increase the concentration of salt in a solution and note when the solution goes from dilute to concentrated to saturated.

Materials

• student sheet (attached)
• 2 test tubes
• balance
• salt
• test tube rack
• graduated cylinder

Background for Teachers

This is an introductory lab to familiarize students with the vocabulary of solutions.

Instructional Procedures

1. If students are unfamiliar with the necessary vocabulary, create flashcards with the terms: solution, solute, solvent, concentration, percent concentration, concentrated, saturated, dilute, precipitate and dissolve. The terms will be used without definition in the lab, so it is important that they are familiar with them.
2. Read the introduction and procedures to the students. Model for them the "think aloud" where as you read and come across a term you (or they) may not understand, you go to your flash card.
3. Give student groups time to perform the experiment.
4. Summarize class results by having students place the percent concentration of their most concentrated solution right before the precipitate formed. Salt will form about a 25% solution at room temperature. Do a class average.
5. Have selected students read their conclusions to the class.

Bibliography

Lesson Design by Jordan School District Teachers and Staff.