The Balloon Race

DRIVING QUESTION: How much Sodium Bicarbonate does it take to blow up a balloon?

PURPOSE: The purpose of this experiment is to identify the limiting and excess reactant in each situation of the gas generated in the balloons from the reaction between acetic acid and baking soda.

INTRODUCTION: In this project, you will combine baking soda and vinegar in various quantities. By observing the amounts of gas generated, I will be able to identify the limiting and excess reactant in each situation.

MATERIALS:

• Balance (0.01 g precision)

• Weighing dish, 6

• Graduated cylinder, 25 mL or 50 mL

• Erlenmeyer flask, 125 mL, 6

• Funnel Powder

• Balloons, 6

• Spatula

• Permanent marker

• Sodium bicarbonate, 10.5 g

• Acetic acid, 1 M, 150 m

PROCEDURE:

1. Label six Erlenmeyer flasks from 1 to 6. Using the graduated cylinder, measure 25 mL acetic acid and to each flask.

2. Label six weighing dishes from 1 to 6. Mass 0.50g, 1.00g, 1.50g, 2.00g, 2.50g, and 3.00g of sodium bicarbonate in each of the labeled weighing dishes.

3. Obtain six balloons and label them 1 to 6. Stretch them to allow for easy expansion. Using the funnel, add the sodium bicarbonate from the weighing dishes to each of the balloons.

4. Holding the balloon to one side carefully to avoid dropping the sodium bicarbonate into the acetic acid stretch the opening of the balloon over the mouth of the flask. Repeat the process so that each balloon with the baking soda is placed firmly over each labeled flask.

5. Line up the Erlenmeyer setup from 1 to 6. With the team members working together, raise the balloons to allow the powder to fall into the acid in the flask at the same time. (Make sure the balloon is firmly fixed to the flask.)

6. Allow the reactions to occur till the bubbling stops. Make your observations and collect data.

7. After the reaction is complete compare the volume of the balloons.

8. Discuss your hypothesis about the observed reactions and the stoichiometric relationships for each reaction. Write chemical equations and explanations for the reactions.

SCIENTIFIC PRINCIPLE/ESSENTIAL UNDERSTANDING: Some formulas that we used was the formula for Sodium Bicarbonate which is NAHCO3. We also used Acetic Acid which was C2H4O2.

NaHCO3 + HC2H3O2 → NaC2H3O2 + H2O + CO2.

Questions

1. Write the balanced equation for sodium bicarbonate with acetic acid forming carbon dioxide, sodium acetate and water.

HC2H3O2 + NaHCO3  NaC2H3O2 + CO2 + H2O

2. What is a limiting reactant?

When there is not enough of one reactant in a chemical reaction, the reaction stops abruptly. To figure out the amount of product produced, it must be determined reactant will limit the chemical reaction (the limiting reagent) and which reactant is in excess (the excess reagent). One way of finding the limiting reagent is by calculating the amount of product that can be formed by each reactant; the one that produces less product is the limiting reagent.

3. Did the limiting reactant change in this lab? How is that possible?

Yes, it is. That is the reason limiting reactant depends on amount of matter.

4. What observations supported your calculations of limiting reactant?

Limiting reactant changed after 3th flask.