Is it possible to change the freezing and boiling point of a substance?
The “normal” freezing point of water is 32oF, but is it possible to change that? By adding salt to water, its freezing point is lowered. Another way of taking advantage of water’s colligative properties is experimenting with water vapor pressure. If the water vapor pressure above water is lowered, then the boiling point of the water will also be lower. This can cause water to boil at even room temperature! Check the demonstrations below to see how adding salt of changing vapor pressure can change freezing and boiling points.
- What is a colligative property and how does it differ from a chemical property?
- Antifreeze is used to prevent automobile engines from boiling over. How does the antifreeze elevate the boiling point and thus prevent the car from boiling over? Does it matter what solutes are in the antifreeze?
- What would happen if the vapor pressure above water was increased? How would that affect the boiling point?