Hot Ice Crystal Towers
Secondary | Materials | Views: 57748
Did you Know?
- Sodium acetate or hot ice is an amazing chemical you can prepare yourself from baking soda and vinegar. You can cool a solution of sodium acetate below its melting point and then cause the liquid to crystallize.
- The crystallization is an exothermic process, so the resulting ice is hot.
- Solidification occurs so quickly you can form sculptures as you pour the hot ice.
Health and Safety: This experiment involves boiling solutions. Please take care when doing so and ensure you have adult supervision.
You will Need:
- 4 tablespoons of baking soda
- 1 litre clear vinegar
The concepts it illustrates are:
- Supercooling
- Crystallisation
- Exothermic Chemical Reactions
What to Do:
- In a saucepan, add baking soda to the vinegar, a little at a time and stirring between additions. The baking soda and vinegar react to form sodium acetate and carbon dioxide gas. If you don’t add the baking soda slowly, you’ll essentially get a baking soda and vinegar volcano, which would overflow your container.
- You’ve made the sodium acetate, but it is too dilute to be very useful, so you need to remove most of the water. Here is the reaction between the baking soda and vinegar to produce the sodium acetate: Na+[HCO3]– + CH3–COOH → CH3–COO– Na+ + H2O + CO2
- Boil the solution to concentrate the sodium acetate. You could just remove the solution from heat once you have 100-150 ml of solution remaining, but the easiest way to get good results is to simply boil the solution until a crystal skin or film starts to form on the surface. This should take about an hour on the stove over medium heat. If you use lower heat you are less likely to get yellow or brown liquid, but it will take longer. Some discolouration is normal.
- Once you remove the sodium acetate solution from heat, immediately cover it to prevent any further evaporation. Pour the solution into a separate container and cover with plastic wrap. You should not have any crystals in your solution. If you do have crystals, stir a very small amount of water or vinegar into the solution, just sufficient to dissolve the crystals.
- Place the covered container of sodium acetate solution in the refrigerator to chill and await the amazing results!
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