Water's boiling point and table salt

In summary, adding salt to boiling water can both lower the freezing point and raise the boiling point. In this case, adding salt caused the boiling water to reach a higher temperature than it normally would without the salt. This is due to the fact that the salt allows the water to absorb more energy before reaching its boiling point. This phenomenon is also true for cooling water, as salt water can get much colder before freezing than pure water.
  • #1
ethomas
2
0
I was doing a simple experiment with my class to demonstrate the boiling point of water.Two of the students wanted to see what would happen when we added salt. So, the students added about 50 ml of common table salt to less than 200 ml of boiling water. The temperature of the water immediately jumped from 215 degrees Fahrenheit, to 226 degrees Fahrenheit. I read in another thread that salt lowers the boiling point of water. Is that true? Or does it increase the boiling point? And why is this? Please use simple language as I am years past my high school chemistry class and was never very good at chemistry anyway (in college I passed only thanks to the wonderful curve!).
 
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  • #2
Salt both lowers the freezing point and raises the boiling point of water.

Pure water, at sea level, boils at 100 degrees celsius (212 F). Once water begins to boil, it stops increasing in temperature, after which, all the energy that is trying to heat the water up is goin g into boiling it.
So when you dissolved all that salt into the already boiling water, you raised the boiling point, allowing the water to get hotter than it normally would have without the salt. The same is true for cooling water, salt water can get much colder without freezing into ice than pure water.
 
  • #3
thanks

Thanks for your reply- it was very helpful.
 

1. What is the boiling point of water?

The boiling point of water is 100 degrees Celsius or 212 degrees Fahrenheit at standard atmospheric pressure.

2. Does adding table salt affect the boiling point of water?

Yes, adding table salt to water can affect its boiling point. A solution of water and salt has a higher boiling point than pure water, meaning it will take longer to reach its boiling point.

3. How much table salt should be added to water to increase its boiling point?

The amount of table salt needed to increase the boiling point of water depends on the amount of water and the desired increase in boiling point. Generally, a good rule of thumb is to add 1 tablespoon of salt for every 4 cups of water.

4. Why does adding table salt increase the boiling point of water?

Table salt, or sodium chloride, is a solute that dissolves in water, forming a solution. This solution has a higher boiling point because the salt particles disrupt the hydrogen bonds between water molecules, making it harder for them to escape into the air as vapor.

5. Does the type of salt used affect the boiling point of water?

Yes, different types of salt can affect the boiling point of water differently. For example, table salt (sodium chloride) will have a greater effect on the boiling point than sea salt (a mixture of various salts). However, the difference may not be significant unless large quantities of salt are added.

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