Reef Chemistry Question of the Day #197 Boiling Point of Seawater

[HOOPDEEZ]

A!

 

[Randy Holmes-Farley]

Any final comments before I post the answer?

 

[saltyphish]

give me a min pl

 

[saltyphish]

d

 

[saltyphish]

d

I know adding salt seems to make it boil quicker and also the same when using in a vaporizer. Maybe making it better at heat transfer, more conductive. More energy is required but less time.

 

[Randy Holmes-Farley]

And the answer is...C. 100.5 °C

Salts in water do lower the freezing point, but they raise the boiling point.

Here's an easy way to think of this...

At the boiling point, water equally likes to be in the liquid or gas phase.

When you have salts in water, the water molecules "prefer" to interact with the dissolved ions compared to just interacting with other water molecules. So the dissolved salts make the water molecules prefer to be in the salty water relative to the gas phase at the normal boiling point. When they want to stay longer in the water, it is harder to boil them off, and the boiling point rises.

That said, the effect is fairly small.

 

[beaslbob]

dern

I thought I answered this with a c also. guess not.

I snoozed and loozed.

 

[Randy Holmes-Farley]

I'll have another C in a few days.