How to Make Solutions for Chemistry and Biology Experiments

Introduction to Solutions

• Solutions are mixtures of one or more substances (solute) dissolved in a liquid (solvent).
• Used in various fields like chemistry, biology, cooking, and materials science.
• Must be homogeneous, meaning uniform in composition.

Types of Solutions

• Liquid Solutions: Most common, e.g., sugar in water.
• Gas Solutions: Gases can dissolve in liquids; homogeneous gas mixtures also count as solutions.

Steps to Make a Solution

1. Decide on Concentration

   • Determines the amount of solute in the solvent.
   • Example: A 10% saline solution has 10g of salt in 100mL of water.

2. Calculate Solute and Solvent Needed

   • Based on desired concentration and total solution volume.

3. Safety Precautions

   • Use gloves and goggles, especially with hazardous or sterile solutions.

4. Measure the Solute

   • Use a scale for solids (accuracy to 0.1g) or measuring tools for liquids.

5. Dissolve the Solute

   • Mix solute with part of the solvent until dissolved, then add remaining solvent.

6. Safety and Quality Checks

   • Check properties like pH and adjust as necessary.

7. Label and Store

   • Label with solution name, concentration, and preparation date.

Expressing Concentration of Solutions

1. Mass/Volume Percentage (%m/v): Mass of solute per 100mL of solution.
2. Volume/Volume Percentage (%v/v): Volume of solute per 100mL of solution.
3. Molarity (M): Moles of solute per liter of solution.
4. Mole Fraction: Ratio of moles of solute to total moles in the solution.

Calculating Solution Concentrations

• Requires knowing two out of three: solute amount, total solution amount, concentration.
• Algebraic methods can be used to find the missing value.

Hands-on Projects to Learn About Solutions

• Projects like measuring solubility, rock candy crystals, and mixing behaviors to understand solution properties and preparation.

Resources

• Includes video tutorials and example calculations to aid understanding.

By following these guidelines and practices, solutions can be prepared accurately and safely for various scientific applications.