Lesson 6.11: Chemical Reactions & Engineering Design
Three Types of Heat Packs
- The first contains a fine iron powder, salt, and water in a pouch that is permeable to air. When it is exposed to air, the iron begins to rust. This rusting process produces heat.
- The second contains a solution of the chemical sodium acetate and a small metal disc. When the disc is bent, crystals of sodium acetate begin to form. This process of changing from a liquid to a solid produces heat.
- The third contains a type of magnesium sulfate, and a pouch of water. When the pouch is broken, the water begins to dissolve the magnesium sulfate. Dissolving this type of magnesium sulfate produces heat.