# What Is a 1 Molar Solution? Mark as Favorite (30 Favorites)

DEMONSTRATION in Concentration, Molarity, Mole Concept. Last updated October 14, 2019.

### Summary

In this demonstration, students will determine the molarity of several different solutions demonstrated by the teacher.

High school

### Objectives

By the end of this lesson, students should be able to

• determine the molarity of several different solutions.

### Chemistry Topics

This lesson supports students’ understanding of

• Solutions
• Mole concept
• Molarity

### Time

Teacher Preparation: 5 minutes

Lesson: 20 minutes

### Materials

• One of each of the following:
• 2000-mL beaker
• 1000-mL beaker
• 500-mL beaker
• 250-mL beaker
• 100-mL beaker
• 3 plastic cutouts of moles

### Safety

• There are no special safety considerations for this lab.

### Teacher Notes

• Before the demonstration:
• Gather beakers all supplies listed above.
• You may also use stuffed moles or plastic moles instead of paper cutouts.
• Have students finish the prelab questions and discuss the answers.
• For the demonstration:
• Demonstrate the mole concept by placing one mole in the one liter beaker and add water to the 1L mark. Indicate that this is a 1 Molar solution.
• Then move the mole into each of the other beakers filled with water and ask the students what the molarity of the new solution is.
• I repeat for the 2 mole situation by asking first which size beaker would be needed in order to create a 1 molar solution using 2 moles of solute. Then complete the process for that row.
• Repeat this process again for the 3 mole row. Begin again by asking what size beaker would be needed in order to create a 1 molar solution using 3 moles of solute.
• Finally rip one mole in half and repeat the process by placing the half mole in each of the beakers.
• Optional: Demonstrate making a 1 molar solution of salt using the correct technique in a volumetric flask.

### Prelab Questions

1. What is a mole? ____________________________________________________________
2. What is the mass of a mole of oxygen atoms? _________________________________
3. What is the mass of a mole of water molecules? _______________________________
4. A 1 molar solution is one in which ____ mole of any substance is dissolved in enough water to make up a total of ____ liter of solution.
5. Molarity is defined as “a unit of concentration used in chemistry to indicate how strong or weak a solution is”. Its symbol is ______ and its units are ____________________________________.

### Results/Observations

As you watch the demonstration, fill in the molarity of each solution when either 1, 2, 3, or ½ moles is added to each beaker.

 # of Moles 2000 mL beaker 1000 mL beaker 500 mL beaker 250 mL beaker 100 mL beaker 1 2 3 1/2

### Analysis

1. Circle the correct answer within the ( ) for each statement below.
- The higher the molarity, the (more concentrated … less concentrated) the solution.
- The lower the molarity, the (fewer … greater) the number of particles the solution.
2. Describe two ways to make a 0.5 molar solution.