Background: A neutralisation reaction takes place inside the bag. The baking powder and the vinegar eventually mix (using a tissue gives you a little bit of time to zip the bag shut). When they do mix you get an acid-base reaction and the two chemicals react together the general equation for this is: Acid + Metal Carbonate Salt + Water + Carbon dioxide. The carbon dioxide is in a gaseous state. Gases take up more volume than solids and liquids, the carbon dioxide gas fills the bag. The pressure of the gas inside the bag keeps increasing until the bag cannot withstand the pressure anymore.

One small (sandwich size)
zip lock bag (ones suitable for the freezer work best).
Baking powder.
Warm water.
Vinegar (white vinegar works best, but the usual vinegar also works well).
Measuring jug.
1x tissue.
Teaspoon.
1. *** Do this experiment outside ****
2. Pour 60ml of warm water into the bag.
3. Add 120ml of vinegar to the water in the bag.
4. Open out a tissue. In the centre put 3 heaped teaspoons of baking powder.
5. Fold the tissue around the baking powder (wrap the baking power up in the tissue).

Work very quickly for the next stage!

6. Zip the bag ¾ closed (only leaving enough room to add the tissue containing the baking powder).
7. Put the tissue containing the baking powder into the bag and quickly seal the bag closed.
8. Put the bag on the ground (outside) and quickly step away.
9. If your bag is completely sealed, the carbon dioxide evolved will be trapped in the bag.

Does water at different temperatures affect how fast the bag inflates?
What amount of baking powder creates the best reaction?
Change the size of the bag. What size creates the fastest pop?

What did you discover?
How did you create the ultimate exploding lunch bag?

Tweet or email your conclusions/findings to:
#chemistry4all #LJMU_CfA #explodinglunches4all  chemistryforall@ljmu.ac.uk

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