Solutions Lab

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Objective

Students will be able to gain practical experience working with a solute, solvent, and a solution.

Big Idea

Solutions are made of a tiny bit of solute and a large quantity of solvent. In this lab your students will dissolve sugar (solute) into water (solvent) to make sugar water (solution). Practical experience helps reenforce these concepts.

NGSS Background

This lesson is based on California's Middle School Integrated Model of NGSS.

NGSS Performance Expectation (PE): (MS-PS1-2) Analyze and interpret data on the properties of substances before and after the substances interact to determine if a chemical reaction has occured.

Science and Engineering Practice (SP) 3: Planning and Carrying out Investigations

Disciplinary Core Ideas (DCI): PS1.A: Structure and Properties of Matter - Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms.

Crosscutting Concepts (CCC): Cause and Effect - Cause and Effect relationships may be used to predict phenomena in natural or designed systems.

Solutions are mixtures that evenly distribute their contents in a container. Comparing and contrasting suspensions and solutions, suspensions would be like a solid where every bight is different and solutions are like vanilla pudding where every bite is the same. Use the activity Suspension Lab to compliment this activity.

During this laboratory activity no chemical reaction takes place (MS-PS1-2). The students will follow precise directions to create a solution mixture (SP3). Once they have created the sugar solution they will attempt to determine if a chemical reaction took place (see Types of Chemical Reactions for review), and practice making a solution using terms such as; solute (sugar), solvent (water), and solution (sugar water). They will learn that pouring a solute (sugar) into a solvent (water) causes the covalent sugar molecules to dissolve into a solution (sugar water) (PS1.A) (CCC). 

Set-up (Prelab)

15 minutes

Materials

  • 150 ml beaker
  • Sugar
  • Spoon
  • Stir rod
  • Triple beam balance scale
  • Goggles (4)

 

Directions

  1. Weigh the empty beaker on the triple beam balance. Record in box ‘B’.
  2. Fill the beaker with 60 ml of water.
  3. Weigh the beaker + water on the triple beam balance scale. Record in box ‘A’.
  4. Subtract the empty beaker weight from the beaker + water weight. Record in box ‘C’. (A-B=C).
  5. Add one spoonful of sugar to the beaker. Stir until dissolved.
  6. Continue adding sugar one spoonful at a time. Stir after each spoonful is added.
  7. Stop when you can observe sugar in the solution even after you have stirred the solution.
  8. Weigh the sugar solution. Record in box ‘D’.
  9. Subtract the beaker + water weight from the sugar water solution + beakerweight. Record in box ‘E’.
  10. Compare the water weight to the sugar weight. Use (>) greater than, (<) less than, or (=) equal to symbol.

 

Data

Beaker + water weight

A

 

 

 

-

Empty Beaker                                            

B

 

 

 

=

Water weight                                             

C

 

 

 

Sugar water solution + beaker weight

D

 

 

 

 

-

Beaker + water weight

A

 

 

 

 

=

Sugar weight

 

E

 

 

 

Water weight

C

 

 

 

Sugar weight

E

 

  

Student Activity (Lab)

15 minutes

Pass out a copy of Solution Lab to each student. This may seem like a simple lab, but practical experience working with terms such as solute, solvent, and solution are vital to understanding these terms and how they are used.

Step 3 - Weighing the beaker and the water (solvent).

 

Step 5 & 6 - Adding sugar (solute) to the water (solvent) to create sugar water (solution).

 

Student Work Sample

 

Extension

25 minutes

To better assist my students in learning about solutions and suspensions I teach the following memory devise.

SOLUTE + SOLVENT = SOLUTION

The solute is the material that is dissolved and the solvent is the material that is doing the dissolving to form the solution. In other words salt (solute is dissolved in water (solvent) making saltwater (solution).

I teach my kids to count the letters. Salt is the smallest letter and it represents the smallest ingredient (solute - 6 letters). Water is the next largest ingredient and it is represent with a larger word (solvent - 7 letters). Saltwater is the largest material is this example and it is represented with the largest word (solution - 8 letters).

I have created a Solutions PowerPoint lesson that can be used with your students that reviews solutions and suspensions.