WHAT YOU CAN EXPECT FROM SOMETHING CALLED HOT ICE:
When you think of ice, you probably think of a cold frozen substance. Ice really is just molecules put together in a certain pattern. Then, the ice is cut and shaped into the blocks we know as ice today. Sodium acetate is cooled below it's freezing point, but it is still a liquid. When the solution, that you will make, is touched by a metal spoon, it starts a chain reaction from the spot where you touched it. The solution will start to form crystals that spread out from where you touched it. Soon the container will be a sheet of crystal, looking kind of like when Elsa, from Disney's Frozen, ran across the river, creating ice that spread out from where her foot is placed.
Elsa's foot is like the spoon, where the crystals form shooting out from that point. The sodium acetate will be like the river, liquid, but when the spoon hits the solution will form crystals from that point. The crystal residue on the spoon is referred to as the "seed." When the solution is exposed to the seed, the crystalline growth starts from the point moving outwards. After the reaction, the container will feel hot. When the crystals were forming, they released heat. Therefore, this chemical reaction is exothermic. That's what this is all about!
Note: The bold words are defined in the vocabulary section at the bottom of the page.
MATERIALS: You are going to need the following items...and maybe a celebration cake once you've dug this out of your cabinet.
- Clear vinegar (around one liter)
- Baking soda (around four tablespoons)
- Heat sorce/ stove
- Dish/ container (to pour the sodium acetate into)
- Press 'n seal/ plastic wrap/ another protective cover
- Metal spoon (optional for chemistry concept demonstrations)
PROCEDURE: The procedure is fairly simple, but it can be disastrous if you don't follow the instructions below.
- Combine one liter of vinegar and four tablespoons of baking soda in the saucepan. Make sure to add small amounts at a slow pace to make sure you don't get a baking soda and vinegar volcano. It is normal for a reaction to occur, even if you are adding the baking soda slowly. This reaction is forming sodium acetate and carbon dioxide gas. Now, you've made sodium acetate, but it's too diluted to be useful.
- Boil the solution to concentrate the sodium acetate. When a crystal film covers the top of the solution, then you should take it off the heat. The timing will be different depending on the heat of your stove. If you encounter discoloration it is probably due to high heat. The color will not change the end result, but if you would like to have a clear solution low heat is probably your best bet.
- Once you take the sodium acetate off the heat, crystallization might occur. That's okay.
- Pour the sodium acetate into a container. Then cover immediately with plastic wrap, press'n seal, or another protective cover. Put the sodium acetate into the refrigerator. You can remove the solution in one to two hours.
- Once the solution has set over night, you should first remove the sodium acetate from the refrigerator. Touch the surface of the liquid with your finger or a metal spoon. Crystallization should start to occur. This is an example of a exothermic reaction. Heat is released as the "ice" forms. Feel the container. You should note, that even though the solution just came out of a cold refrigerator, the container feels hot.
- First, take the solution out of the refrigerator. Pour the solution into a shallow dish. Crystallization should start when the liquid hits the bottom of the container. The crystallization will continue as the sodium acetate forms a "tower" up towards where you are pouring from. The tower will feel hot to the touch. This again is an example of an exothermic reaction. (THIS WAS NOT DONE IN THE VIDEO DEMONSTRATION)
- Salt- Any chemical compound formed from the reaction of an acid with a base
- Acetic acid- A acid that is most commonly found in vinegar
- Carbon dioxide gas- A colorless, odorless, and non harmful gas that is in the air you breath. (around 0.03 percent)
- Diluted- Refering to a substance that is watered down to make a liquid thinner or weaker
- Concentrate- A subatance made when removing the water from a diluted substance
- Crystallization- A solid-liquid separation where the mass is transferred from a liquid solution to a solid with a set three dimensional pattern for its molecules
- Exothermic reaction- (Chemical) A reaction where more energy is released than is absorbed; reaction will feel hot