Running the Experiment

Pour about 25 mL of deionized water on top of your Pop Rocks™ sample and VERY quickly replace the distillation head.

Turn on the burner and heat the Pop Rocks™/water solution.

Allow the Pop Rocks to dissolve in the solution until the reaction flask stops "fizzing" and bubbling. All of the solid Pop Rocks™ sample should be completely dissolved. No solid candy should be visible in the boiling flask.

While the reaction is taking place, fill a 50 mL buret with 0.1 M HCl (standardized and provided by the laboratory staff).

Once the fizzing has stopped, take the receiving flask off of the apparatus. Swirl it a few times. Squirt water using your deionized water bottle through the distillation tube and into the receiving flask. Then pour the contents of the receiving vessel (the one originally containing NaOH) into a clean, dry 250 mL beaker. Add 2-3 drops of phenolphthalein.

Record the initial volume on the buret. It does not have to be a exactly 0.00 mL.

Titrate the solution from the receiving vessel to the endpoint with HCl, when the phenolphthalein should appear a very light shade of pale pink. Add the HCl solution from the buret a few drops at a time. Swirl the beaker in between additions. When you have reached the endpoint, record the volume of HCl added. To be sure that you have reached the endpoint, you should compare your beaker with one the TA will provide, showing the correct color of the phenolthalein endpoint.

Record the final volume on the buret to the nearest hundreth of a milliliter.

Add 2-3 drops of methyl orange to the beaker.

Refill the buret to about the 25.00 mL mark with HCl. Record the initial volume.

Titrate the solution again to the endpoint, where the methyl orange should appear red. Again, add the HCl solution from the buret slowly, a few drops at a time. Swirl the beaker in between additions. When you have reached the endpoint, record the volume of HCl added. To be sure that you have reached the endpoint, you should compare your beaker with one the TA will provide, showing the correct color of the methyl orange endpoint.

Record the final volume on the buret to the nearest hundreth of a milliliter.

You’ve completed a distillation and two manual titrations. You now have the tools to successfully determine how much carbon dioxide is contained in one gram of Pop Rocks™.

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