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| | [[File:Dominica boiling lake.jpg|thumb|A boiling lake in [[Dominica]]]] | | [[File:Dominica boiling lake.jpg|thumb|A boiling lake in [[Dominica]]]] |
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| − | The '''boiling point''' of a [[substance]] is the [[temperature]] at which the substance boils, or enters a state of rapid [[evaporation]]. For pure [[water]] this is 100° [[Celsius]] or 212° [[Fahrenheit]]. This is measured at one [[Atmosphere (unit)|atmosphere]], that is, the air pressure at [[sea level]]. | + | The '''boiling point''' of a [[substance]] is the [[temperature]] at which the substance boils, or enters a state of rapid [[evaporation]]. For pure [[water]] this is 100° [[Celsius]] or 212° [[Fahrenheit]]. This is measured at one [[Atmosphere (unit)|atmosphere]], that is, the air pressure at [[sea level]] |
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| − | Boiling points can be changed in several ways. The addition of [[solute]]s or other substances usually changes the boiling point. Changing the [[pressure]] on a liquid changes its boiling point. | + | Boiling points can be changed in several ways. The addition of [[solute]]s or other substances usually changes the boiling point. Additionally, changing the [[pressure]] on a liquid changes its boiling point. |
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| | The boiling point of a liquid depends on the [[pressure]] of the surrounding air. An increase in air pressure increases the boiling point; a decrease decreases the boiling point. In the low pressure environment at the top of Mt Everest for example, water boils at only 69 °C. (156.2 °F). | | The boiling point of a liquid depends on the [[pressure]] of the surrounding air. An increase in air pressure increases the boiling point; a decrease decreases the boiling point. In the low pressure environment at the top of Mt Everest for example, water boils at only 69 °C. (156.2 °F). |
| | It can also be defined in terms of [[vapour pressure]] as the temperature at which vapour pressure of liquid becomes equal to atmospheric pressure | | It can also be defined in terms of [[vapour pressure]] as the temperature at which vapour pressure of liquid becomes equal to atmospheric pressure |
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| − | If you add [[sugar]], [[salt]] or any other [[impurities]] to the water, it will usually make the boiling point higher. An exception is [[alcohol]], which will have a lower boiling point.
| + | [[Sugar]], [[salt]] or other non-volatile [[solute]]<nowiki/>s in water will usually make the boiling point higher. [[Alcohol]], in contrast, is a volatile chemical that lowers the boiling point of water. Even a large amount dissolved in the water will usually make only small changes in the boiling point.{{physics-stub}} |
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| − | {{physics-stub}} | |
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| | [[Category:Thermodynamics]] | | [[Category:Thermodynamics]] |
| | [[Category:Basic physics ideas]] | | [[Category:Basic physics ideas]] |