what does table salt do to the boiling point of water? what happens to the salt? does it really boil?

Question

I CANT FIND THE ANSWERS ANYWHERE >> THESE ARE THE QUESTIONS I NEED TO ANSWER FOR A CHEM PROJECT

Answer 1

When you dissolve “salt” in water, the boiling point of the resulting solution is higher than the boiling point of the pure water.
The boiling point goes up (and the freezing point goes down) when you dissolve a salt (such as NaCl, also known as ‘table salt’) in water.

When the solution does boil, the salt dissolved in the water does not boil away, just the water. Water boils off the solution leaving the salt behind, resulting in a more concentrated solution. If one cools and condenses the vapors coming off of the boiling solution one would be left with pure H2O. If one boils the solution long enough and boils off enough water, eventually you will exceed the amount of salt which is capable of dissolving in the amount of water left and you will get a solid precipitate. This method can be used to separate salt and water when the two are mixed.

Answer 2

Why does adding salt make the boiling temperature of water rise??? soeun lee (age ) Auckland Girls Grammar Auckland, New Zealand A: Souen- That's a good question. It turns out to be easy to give an answer to someone who's studed a little Statistical Mechanics, but I'll try to give an answer that doesn't assume that sort of background. Salt (or other solutes, like sugar) can easily dissolve in liquid water. However, taking the solute out of the water and putting it in the gas phase (air) requires a lot of energy. At temperatures around the water boiling point, these solutes stay in the liquid. Now the total pressure in the liquid and the air at the boundary are the same- otherwise one would push the other into a smaller space. Part of the pressure in the liquid comes from the solutes, not the water. So the pressure due to the water alone is reduced compared to that of pure water at the same temperature. The vapor pressure, that is, the pressure of water vapor that would stay in equilibrium with the liquid, is reduced by the same amount because of the solutes. Water boils when the vapor pressure of the water gets to be as big as the pressure of the atmosphere. At that point, vapor bubbles in the water can grow. You have to heat the liquid with solutes up more to get the vapor pressure in it to equal the atmospheric pressure, so it has a higher boiling point. A very similar argument explains why solutes also lower the freezing point. Since the solutes are almost completely excluded from the solid (like from the gas) they stabilize the liquid. A search of this site will turn up some answers about freezing salt water.

Answer 3

Water boils when its vapor pressure equals the pressure of the atmosphere above the water. As we heat water, its vapor pressure increases and eventually, the vapor pressure of the water will equal the atmospheric pressure and the water will boil.

Adding salt to water causes the vapor pressure of the water to decrease at all temperatures. This means that the saltwater must go to a higher temperature for the vapor pressure to reach atmospheric pressure. The boiling point increases.

The salt just stays dissolved in the water. It does not boil. Only the water boils and changes into water vapor (but at a higher temperature than the water without the salt).

Answer 4

When salt or sugar are dissolved in water, they raise the boiling temperature. They reduce the fraction of water molecules at the surface of the water, so that fewer leave each second. Because of this reduced leaving rate, the water has to get hotter before enough water molecules will leave each second to allow evaporation to occur inside the liquid (i.e. for the water to boil). As for the value of adding salt, sugar, or any other material to water to encourage boiling, that is a very different matter. Adding anything that can serve as a site for bubble formation will help the water to boil. Nucleating the tiny bubbles that eventually grow into the large bubbles we associate with boiling isn't easy. Often it occurs at a hot spot in the pot, or near a defect on the pot's inner surface. If there aren't any hot spots or defects, then adding sharp objects will aid bubble formation. That's why sprinkling sugar or salt into extremely hot water can help it boil. This boiling occurs before the sugar or salt dissolve. They are just acting as nucleation sites. You'd do just as well to add sand, which doesn't dissolve

Answer 5

Salt does raise the boiling point somewhat. As water boils the salt stays behind.

Answer 6

It raises the boiling point. The salt is a residue when the water is boiled off. Salt does not boil at the boiling pont of water alone it sublimates.

Answer 7

Table salt causes the temperature at which water boils to rise. Salt dissolving in water causes this.

Answer 8

Nothing to do with surface area. The salt raises the boiling point of water instead of being 100.0 C it would be something slightly higher. Slightly speeds cooking time.

Salt also slightly desiccates the outer surface of pasta and vegetables, so when they finish boiling the outer surface is slightly toughened.

This same process is used to “brine” turkeys prior to cooking. This help to keep some of the moisture in.

Answer 9

the salt dissolves in the water making a saline solution, this solution has a higher boiling point than that of pure water because the salt lower the vapor pressure of the water, and you can only boil a solution when the vapor pressure is equal to that of the external pressure, so the easiest way to increase vapor pressure is to add heat and you have to add more heat to overcome the atmospheric pressure due to the drop in vapor pressure of the solution due to the salt.

Answer 10

I believe the addition of salt slightly increases the boiling point of water. (Salt also decreases the freezing point of water, which is why we apply salt to icy roads.) When the salt is added to water it dissolves, and it actually dissociates, or comes apart into its component parts. Table salt is NaCl (sodium chloride). Thus, the water has positive Na ions and negative Cl ions in it.