University of Virginia Physics Department Chemical Change with Mixed Solutions A Physical Science Activity

Student Activity

Materials

• 30mL of sodium hydroxide prepared in advance
• 5 grams of cupric nitrate powder
• Two 100 mL beakers
• Paper for weighing chemicals
• Stirring rod
• Graduated cylinder
• Balance
• Scoopula

Procedure

Safety glasses and aprons should be used, avoid touching or tasting chemicals.

1. With your balance mass out 4.8 grams of copper nitrate on a piece of paper.

   (When massing chemicals on most balances, paper or some type of container must be used to keep the chemical from coming in contact with the metal pan because the chemical may be corrosive. The paper or container must be massed before placing the chemical on it, and then again with the chemical on it. The two masses must be subtracted to obtain the mass of the chemical alone if using a triple arm balance. When using an electronic balance the "tare" function will remove the mass of the paper or container.)

2. Measure out 25 mL of water in a graduated cylinder and pour it into a 100 mL beaker.
3. Empty the copper nitrate into the beaker of water and stir until the mixture is completely dissolved. Let the beaker and solution remain on the balance.
4. Place the second beaker on the balance, measure out 25 mL of the sodium hydroxide solution.
5. While both solutions are on the balance in separate containers, record the mass. Enter the value in the data section below under "mass of beakers and contents before reaction."
6. Pour one of the beakers into the other, observe the reaction and record the mass of both the empty and full beakers again. Enter the value in the data section below under "mass of beakers and contents after reaction."

Data Sheet

Mass of Beakers and Contents Before Reaction Mass of Beakers and Contents After Reaction ___________________ ___________________   Describe the solution that was made when you mixed copper nitrate in water.   Describe the appearance of the sodium hydroxide solution.   What did you observe when you mixed the two solutions together?   Describe the state of matter, color and solubility of the new substance formed.   A double replacement reaction is also called a ion exchange reaction. Describe the exchange of ions that is taking place.   In a double replacement reaction one product must always be an insoluble solid. Which of the products formed in this reaction is the insoluble solid?   In a double replacement reaction one of the products must always be a soluble solid. Which of these products is the soluble solid?   Describe what would happen if the products you obtained in this reaction were filtered through filter paper.