Lowering the atmospheric pressure on a liquid
Boiling Point Lowering with Pressure
Boiling occurs when the vapor pressure of a liquid equals the surrounding atmospheric pressure.
Key Concept: A liquid boils at the temperature where its internal vapor pressure matches the external pressure exerted on it.
Effect of Lowering Atmospheric Pressure
- When atmospheric pressure is lowered, the external pressure on the liquid decreases.
- The liquid's vapor pressure needs to reach a lower value to equal the external pressure.
- Since vapor pressure increases with temperature, a lower temperature is sufficient to achieve this.
- Therefore, lowering the atmospheric pressure lowers the boiling point of the liquid.
For example, water boils at 100°C (212°F) at standard sea-level atmospheric pressure. At higher altitudes, where atmospheric pressure is lower, water boils at a temperature below 100°C.
Important Questions from Chemistry
Common salt (NaCl) is not used as a raw material for preparation of which one of the following compounds?
Which one of the following is the chemical formula of Hypobromous acid?
Which one of the following is not used as a raw material in the manufacture of glass?
Which one of the following statements about dihydrogen (H 2) is not correct?
Reaction of quick lime (CaO) with water to produce slaked lime (Ca(OH) 2) is an example of
