1. How Much Gas? How much gas is created in the reaction of citric acid and sodium bicarbonate?

2. How can we make the gas collection more accurate? Problem- balloon allowed the gas to escape and not all of the gas from the experiment was collected and with other methods it might not give us specific answers Solution- let’s change a few instruments Instead of a balloon, let’s use a syringe with measurement markings on it Check it out on the next slide

3. Bottle & Syringe System To make this, you are going to use a syringe, a stopper and a glass bottle. The syringe stopper will go up as gas in the experiment is produced The syringe has measurement markers to keep it accurate

4. The materials for our lab: Jar of sodium bicarbonate Jar of citric acid 1 spoon, 2-mL Glass bottle #1 rubber stopper with hole 35-mL syringe water Protective eyewear I will have organized these into material cubbies for you to use in class, but make sure everything is returned to the cubby for clean-up Citric Acid Solution: we are going to use a citric acid solution of 2 mL of citric acid/100 mL of water to reduce lab error

5. Here is our lab procedure: Take a material cubby to your lab table. Put on protective eyewear. Put one level 2 mL spoon of sodium bicarbonate into the glass bottle. Put stopper in the opening of the glass bottle. Take up 5 mL of citric acid solution in the syringe. Insert the tip of the syringe into the hole of the stopper. Push the solution into the glass bottle using the syringe plunger. Don’t remove syringe. Observe and record results.

6. Last step… 8. Dump the used experiment into a sink and conduct two more trials. It is NOT necessary to wash out the bottle between trials.

7. To Prepare for Class: Write down the procedure for the lab, because we will not review this during class time. Create a data table to record your observations. It could look like this…

8. Be thinking about these things while completing the lab… What causes the syringe plunger to go up during the reaction between citric acid and sodium bicarbonate? Why is a syringe more useful than a balloon to conduct this experiment? What really causes this reaction the sodium bicarbonate or the citric acid?