Can salt affect the boiling speed of water?

Question

Well, I'm having an experiment in our school. And this is the study in which i turned on to. With your help, I will be able to finish my study!!!!!

Answer 1

There are some flaws in most experiments that attempt to detemine if salt affects the boiling speed of water that you'll have to correct if you want to use the results to show how salt affects the boiling point of water.

The molecules in the liquid are in constant motion. They constantly collide with each other and with the walls of their container; every now and then, a collision will cause one of the molecules to be ejected from the liquid into the air above it, creating a vapor pressure above the liquid. Heating the liquid increases the average speed of the molecules, increases the number of molecules ejected, and increases the vapor pressure.

A liquid boils when its vapor pressure becomes equal to atmospheric pressure. Low atmospheric pressure causes the boiling point to go down; high pressure drives it up. Atmospheric pressure varies a bit from day to day, depending on the weather, and it varies from place to place, depending on the altitude. So it's quite possible that you'll get a boiling point for the salt water that's less than 100°, which seems to contradict what your textbook predicts (namely, that salt increases the boiling point temperature).

You can look at the effect of salt without the pressure effect if you measure the boiling point of the water before adding the salt. That way you can compare the boiling point of the water and the solution at the same pressure.

Another thing that affects the vapor pressure of the water is the relative number of water molecules in the solution. The higher the percentage of water, the more molecules will escape into the vapor, and the higher the vapor pressure will be. A salty solution has a lower percentage of water molecules than pure water does. So dissolving salt in water decreases the vapor pressure of the water. The more salt you dissolve, the lower the vapor pressure of the water becomes. You'll have to heat the solution to a higher temperature than before to get its vapor pressure equal to atmospheric pressure

You must carefully measure the amount of salt you use to be sure that it's salt and not something else that is affecting the boiling point. The boiling point goes up by roughly 1°C for every mole of NaCl per liter- it's a very small effect, and one you're likely to miss completely if you're sloppy or your thermometer isn't very precise.

Finally, make sure that the temperature you're measuring is really the boiling point. The first bubbles that appear aren't steam- they're dissolved air, which comes out of solution as the temperature rises. You won't be at the boiling point until the bubbles forming at the bottom rise all the way to the top and burst on the surface. Don't wait too long; as the liquid boils, some will evaporate, increasing the salt concentration. The boiling point temperature will slowly climb as the experiment proceeds!
The direct answer to your question is that yes, salt does affect the boiling speed of water, but you have to be very careful in determining that it is in fact the salt that is causing the change.
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Answer 2

Boiling Water With Salt Experiment

Answer 3

Adding salt to water will raise the boiling point (above 100 C or 212 F), thus taking longer to boil. Hope that the rest of the experiment goes well. =)

Also, adding salt to water lowers the freezing point (below 0 C or 32 F), which is why we "salt" our icy roads in the winter. Where it would normally be ice at 31 F, with salt, it remains water until a lower temperature, say 29 F. But at really cold temperatures salt is ineffective.

Answer 4

Yes, it lowers the boiling point of the water, so it comes to a boil sooner.

EDIT -- ok, so I was wrong!

"Referring to the specific situation you described: I will assume that the rather
small amount of salt added (relative to the much larger volume of water)will be
completely dissolved well before ebulliation commences. If so, the salted water
will require more exposure to the heat before boiling than would the distilled
water. So the salted water "boils slower" than the distilled water. Nevertheless,
under these real-world conditions of low salt concentration, it would be
difficult to tell which pot boiled first.

Answer 5

Salt, because it's a metal, will raise the boiling point of water and lower the freezing point (which is why ocean water never freezes). Therefore, adding salt to your water will slow the boiling process.

Answer 6

Yes, actually. It makes it boil slower because salt water has a higher boiling point than plain water.

Also, like how you would boil water to cook pasta, you would never put salt into the pot before the water boils because it slows down the process and could scald your pot.

Answer 7

salt will raise the temperature at which water boils so it will take longer to reach the boiling point than fresh water if the same amount is applied to them

Answer 8

It doesn't change a thing. Water is water. Nothing you add will change its boiling point.

Answer 9

Yes, it creates density which creates a thicker molecular mass, which creates shorter time for those molecules to start bumping into each other and thus create that friction we call HEAT!

Answer 10

ahhh i'm in 8th grade and i am doing the exact same thing right now. my title is "Now you're feeling "salty" hah like a play on the word saudy. soo yeah i hope i helped and i hope you dont go to my school or something hah.