What is Salt: Definition and 273 Discussions

Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quantities in seawater. The open ocean has about 35 grams (1.2 oz) of solids per liter of sea water, a salinity of 3.5%.
Salt is essential for life in general, and saltiness is one of the basic human tastes. Salt is one of the oldest and most ubiquitous food seasonings, and salting is an important method of food preservation.
Some of the earliest evidence of salt processing dates to around 6,000 BC, when people living in the area of present-day Romania boiled spring water to extract salts; a salt-works in China dates to approximately the same period. Salt was also prized by the ancient Hebrews, the Greeks, the Romans, the Byzantines, the Hittites, Egyptians, and the Indians. Salt became an important article of trade and was transported by boat across the Mediterranean Sea, along specially built salt roads, and across the Sahara on camel caravans. The scarcity and universal need for salt have led nations to go to war over it and use it to raise tax revenues. Salt is used in religious ceremonies and has other cultural and traditional significance.
Salt is processed from salt mines, and by the evaporation of seawater (sea salt) and mineral-rich spring water in shallow pools. Its major industrial products are caustic soda and chlorine; salt is used in many industrial processes including the manufacture of polyvinyl chloride, plastics, paper pulp and many other products. Of the annual global production of around two hundred million tonnes of salt, about 6% is used for human consumption. Other uses include water conditioning processes, de-icing highways, and agricultural use. Edible salt is sold in forms such as sea salt and table salt which usually contains an anti-caking agent and may be iodised to prevent iodine deficiency. As well as its use in cooking and at the table, salt is present in many processed foods.
Sodium is an essential nutrient for human health via its role as an electrolyte and osmotic solute. Excessive salt consumption may increase the risk of cardiovascular diseases, such as hypertension, in children and adults. Such health effects of salt have long been studied. Accordingly, numerous world health associations and experts in developed countries recommend reducing consumption of popular salty foods. The World Health Organization recommends that adults consume less than 2,000 mg of sodium, equivalent to 5 grams of salt per day.

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  1. D

    How does a salt water capacitor work?

    I made a capacitor following the instructions on this site http://www.instructables.com/id/Make-A-Water-Bottle-Capacitor/ Does anyone know how it works?
  2. V

    Entangled Atoms in Salt: Uncovering the Surprising Results of a 2003 Experiment

    According to Scientific American June 2011: "A neat experiment in 2003 proved that larger systems, too, can remain entangled when the leakage is reduced or somehow counteracted. Gabriel Aeppli of University College London and his colleagues took a piece of lithium fluoride salt and put it in...
  3. O

    Understanding the Salt Engine: Effects of Salt on an Engine

    how does salt turned into an engine affect?
  4. N

    Salt Formation: Attraction of Sodium & Chlorine

    Is the combination of an positive sodium with a negative chlorine neutral ? If so, what attracts and holds together other sodiums and chlorines to make a grain of salt ?
  5. C

    Rate of evaporation in salt water swimming pools

    I am interested in understanding and being able to calulate the rate of evaporation and the volume lose over time of the salt water. Surface area is 190 sf Depth 4' average air temp 75 deg. F Daylight hours 12 Average wind speed 5 mph Humidity 65%
  6. F

    How does Changing Salt Bridge Solution affect observed voltages?

    Homework Statement In a lab in which many half-cells are constructed, one of which contains Zn2+, the original salt bridge solution is Potassium nitrate. Suppose we needed to change this solution to Zinc nitrate. What would be the effect on the observed cell potentials? Homework Equations...
  7. M

    Thorium salt reactors in emergencies

    Now that we've had another cooling incident / incidents, I'm curious how the Thorium fluoride reactor would have faired. I've read that continuous reprocessing of the salt would likely be part of the process. Does this imply that there would be less lag in the system should cooling become an...
  8. W

    Solving Drain Problem: Salt Concentration in Effluent

    drain problem? Homework Statement A tank has 1000 m3 of salt solution. The salt concentration is 10 kg/m3. At time zero, salt-free water starts to flow into the tank at a rate of 10 m3/min. Simultaneously salt solution flows out of the tank at 10 m3/min, so that the volume of the solution...
  9. S

    Sumitomo's New Molten Salt Battery

    Sumitomo Corp and Kyoto University have jointly come up with a new sodium-based molten salt battery which is claimed to have twice the energy density of Lithium-ion batteries, at only 10% the material cost. They hope to bring it to market in 2015...
  10. M

    How is current conducted in a salt solution?

    Imagine you connected the two terminals of a battery to electrodes and stuck them into a salt solution. There would be a current. I realize that the current inside the solution is the flow of the negative Chloride ions towards the cathode and the positive Sodium ions towards the anode. And...
  11. C

    Moles...Moles"Calculate Salt & Water Concentration: 3L & 250g NaCl

    Homework Statement Calculate the concentration of water and table salt, when 250 grams of table salt NaCl is in 3 litres of liquid. Table salt has a molecular mass of 58,5 g/mol. Homework Equations Give the answer in two decimal precision The Attempt at a Solution What do they mean...
  12. R

    Rate of Temperature Measurement (Effect of Salt)

    Can anyone help me with our investigative project in physics? This is just a very simple project. Our experiment is all about the effect of salt on the rate at which a glass thermometer measure a sudden change in the temperature of a solution. The thermometer will first be allowed to be at...
  13. M

    Salt tank differential equation

    Homework Statement Solve problem 23 under the assumption that the solution is pumped out at a faster rate of 10 gal/min. When is the tank empty? 23. A large tank is filled to capacity with 500 gallons of pure water. Brine containing 2 pounds of salt per gallon is pumped into the tank at a...
  14. J

    What is the role of a salt bridge in a Daniell cell?

    What is the function of salt bridge in a daniell cell?Why KNO3 is used in salt bridge ?
  15. F

    Surprising Benefits of Adding Salt to Ice/Water Mixture

    http://www.youtube.com/watch?v=cgAlxBEPEf4&NR=1&feature=fvwp The guy in the video says something like "the salts going to allow the ice to stay at its freezing point without melting." I've always thought that adding salt to ice/water mixture lowers the freezing point, and therefore melts the...
  16. M

    Hydroelectricity - salt vs fresh water

    I am doing doing a science project for school and I didnt get the results i was expecting so I was wondering if somebody would help me :) I wanted to test whether salt water or fresh water would produce more hydroelectric voltage. I expected the salt water to produce more because it is heavier...
  17. T

    Effect of Salt on Cooling of Water

    Homework Statement How does the average rate of cooling relate to saturation of salt in water? Variable: salt, water, surface area of pot/container, initial temp The Attempt at a Solution So, to do this lab I started out with saturated water, and then got progressively less saturated...
  18. E

    Simple Diff EQ - Modeling the salt concentration of a pond

    Homework Statement The problem can be found here: http://alex.fangsoft.net/math.pdf I have completed Task #2, it is Task #1 that I am very lost on. Our teacher has really thrown us head first into the water with this one, I am very unfamiliar with differential equations and their...
  19. D

    Al3+ Concentration at pH 7 from AlCl3 Addition to Distilled Water

    1. What is the saturated [Al3+] concentration at pH7 made by the addition of AlCl3 to distilled water? 2. AlCl3<-->Al3++3Cl- 3H2O<-->3H++3OH- Kw=1x10-14 Al3++3OH-<-->Al(OH)3 Ksp=3x10-34 3. I'm familiar with this type of problem, but not the way in which it's being asked. I...
  20. K

    Flux Density of Salt in Horizontal Tube: How Does Advection Affect Transfer?

    Homework Statement What is the flux density of salt in a horizontal tube, 10cm in length, connecting seawater (salinity 30g/L) to a tank of freshwater (salinity ~0) assuming no advection occurs? Homework Equations J (g/m2s) = C (g/m3) x V (m/s) The Attempt at a Solution C = 30g/L *...
  21. P

    Salt Tank Differential Equation

    Ok so this is the question A tank contains 100 kg of salt and 2000 L of water. A solution of a concentration 0.025 kg of salt per liter enters a tank at the rate 5 L/min. The solution is mixed and drains from the tank at the same rate. A.What is the concentration of our solution in the...
  22. J

    How to Make Mohr's Salt: Water and Solution Amounts Needed?

    When making Mohr's Salt (Ammonium Iron (II) Sulphate) how much water am I required to add OR how much of each solution must I use. Thanks Assuming it is equimolar, how much of each (Iron Sulfate and Ammonium Sulphate) Do i need
  23. C

    A perfect storm in a cup of salt water?

    Hi all: I have been puzzled by a very simple experiment I did lately. I found there exists a temperature gradient in a cup of saturated salt water--the bottom is about 0.5 Celsius warmer than the top. That is after the solution has been left intact for more than 100 hours. There is no such...
  24. L

    Natural preservatives. vinegar, alcohol, sugar, salt, oil.

    there are a lot of natural preservatives. vinegar, alcohol, sugar, salt, oil. what is the best? Is there any predominant research about this topic?
  25. P

    Lemon juice vs Lemon juice + salt

    Hello, I did an experiment to try and clean copper pennies with acids like lemon juice and vinegar. When they are dipped in only lemon juice, nothing happens. However, when you add salt, the effect is almost instantaneous. Why does adding salt to lemon juice (citric acid?) make it a much...
  26. P

    Salt Bridge Reactions: Fe2+ & Mg - Which is Correct?

    Does it matter which way I have the solutions? i.e. is this correct (in a reaction between iron and magnesium): Fe2+ | Fe || Mg | Mg 2+ Or is this correct: Fe | Fe2+ || Mg 2+ | Mg Or are they all correct, as long as I have them on the correct sides of the salt bridge?
  27. C

    Salt Melting Ice: Heat & Cooling Effects

    Why does the salt melt the ice , and if i put a soda in a cooler then put ice on it and then put salt on it , it will start to melt the ice and then cool the soda faster then with just ice alone , is it correct to say that the melting of the ice requires heat , and it pulls the heat from the...
  28. M

    Tomato, Salt Water & Olive Oil - Buoyancy

    Homework Statement 1. You put a tomato into a vessel of salty water - it floats. Now you pour olive oil into the same vessel. Which one of the following statements is true? a. More of the tomato will be above the surface of the water. b. The tomato will stay at the same height. c. Less of...
  29. H

    Tomato, Salt water and Olive oil

    Homework Statement You put a tomato into a vessel of salty water - it floats. Now you pour olive oil into the same vessel. Which one of the following statements is true? a)Less of the tomato will be above the surface of the water. b) The tomato will stay at the same height. c) More of...
  30. S

    Why is electricty conducted through salt water?

    Ok so when I pass electricty through salt water the negative ions move from highly negative area to positive area causing a current? My question is why do the move? Let's say there was Sodium and Chloride ions in water. Can't the chloride ion give an electron to sodium and make the whole...
  31. A

    Salt Bridge Questions: Will Zinc Affect Cell Potential?

    I've just about had it with these salt bridges. It's such an easy concept but there are too many questions about it. I understand that the salt bridge enables the flow of ions for the cathodes and anodes by neutralizing charges, but if you use a different salt bridge (Say zinc nitrate instead...
  32. N

    Salt deposit deterrance by Magnesium rod

    I recently repaired a domestic water heater and had to replace the heater element that was heavily coated with hard water salts as well as the SS (Stainless Steel) tank had a large quantity of salt precipitate; the heater element has the option to have a magnesium rod/ element placed/ coupled...
  33. E

    Unraveling Double Salt Reactions

    How does double salt reactions work? Let's say, Cu(NH4)2(SO4)2 + NaOH --> ?? OR maybe Cu(NH4)2(SO4)2 + BaCl2 --> ? Thanks.
  34. T

    NH4F Salt Solution: Acidic or Neutral?

    Homework Statement A solution of NH_4F would be: a) acidic b) neutral c) basic The Attempt at a Solution I think the solution would be acidic because it is a salt made of a weak acid and a weak base. Since the Ka for HF is greater than the Kb for NH3, the Ka for NH4+ is greater than...
  35. R

    What do DC magnetic fields do to salt water.

    What effect does a DC magnetic field probe have when submerged in salt water ? i.e. There is not an electrode..just a plastic insulator with calcium ions pulsing through it giving off a magnetic pulse submerged in salt water. Sodium ions are paramagnetic, so would these be attracted to the...
  36. E

    Calculating Salt Solution Concentration: Calculus & Non-Calculus Solutions

    There is a tank that contains 10,000 gallons of a weak salt solution. The salt concentration is 1300 parts per million. Now we start adding 130 gallons per minute of water and also remove 130 gallons per minute of salt solution. Thererore the salt solution concentration gradually decreases to...
  37. D

    Effects of Tropical Storms on Salt Marsh Ecosystems

    Large tropical storms can have dramatic effects on coastal, estuarine, and terrestrial ecosystems. The combination of high winds and intense precipitation deposits a large amount of leaves, branches, and mud as well as pollutants into the streams killing some of the living organisms in the...
  38. T

    Solving a Salt Transport ODE: Find Salt After 10 Minutes

    Homework Statement I've attached the relevant pictures. The question is: Let X,Y be two containers. At t=0, container X has 100 lt. of water with 2 kg of salt in it and Y has 100 lt. of water with 6 kg of salt. On each t>0, the system transports water as the you can see in the picture...
  39. 1

    Why anhydrous salt is less soluble in water than hydrous salt

    Homework Statement I just wanted to ask why anhydrous salt is less soluble in water than hydrous salt especially in case of glauber's salt Thank you very much!
  40. icystrike

    Does Alcohol React with Acid to Produce Salt or Ester?

    I am uncertain if alcohol react with acid ( not carboxylic acid ) will produce salt or ester.
  41. M

    Chem I: Determining Acidic, Basic or Neutral Salt

    Homework Statement Predict if the following salts are acidic, basic, neutral or undetermined. Homework Equations a. NaOCl b. NH4I c. Sr(ClO3)2 d. KCN The Attempt at a Solution A. NaClO = Na+ and ClO- So, if Na+ gives up a proton, that would turn it into Na... and...
  42. S

    Salt Concentration in 4000L Tank: Find the Limit

    A tank contains 4000L of pure water. Brine that contains 30g of salt per liter of water is pumped into the tank at a rate of 25L/min. Show that the concentration of salt after t minutes (in grams per liter) is C(t) = 30t/160+t What happens to the concentration as t --> infinity lim C(t)=...
  43. Shackleford

    Solving #12: Salt Content in Tank B

    This is probably the longest problem I've ever had. #12. Check my work, please. I'm a bit leery of the solution to the salt content, y(t), for Tank B simply because it seems quite complicated. The first part wasn't too bad, though...
  44. M

    Sugar, salt and processed foods is finally good for you

    Excellent - froot loops are now good for you (according to their makers) Worried that the government food health labelling is a bit of downer, "you can't eat this, you can't eat that" they have decided to launch their own positive labelling. “Froot Loops is an excellent source of many...
  45. P

    Why is there more rust in a solution with less salt?

    more rust in less salt?? As part of my chemistry experiments on corrosion, I am noticing that the steel nails are rusting more in solutions of 3.5g/L salt, than 35g/L salt. What could be some reasons to explain this?? I would have thought that the 35g/L solutions would have lead to more...
  46. G

    Discover the Fascinating Connection between Sound Waves and Salt | Metacafe

    Is this real? http://www.metacafe.com/watch/416486/salt_sound_waves/ What's happening?
  47. S

    Raising boiling point of salt water

    How much salt per quart does it take to raise the temperature of water to 325 degrees at 28 PSI? I am sorry to say I am not educated in physics but I do understand the more particles in the water the higher the boiling point. I am trying to plasticize animal horns in a pressure cooker with a...
  48. C

    Iodized salt vs. pure kosher salt

    why do chefs prefer kosher salt as apposed to iodized salt they say the iodized reacts with the food to make a funny taste but is this really true or make that big of a difference.
  49. Y

    Explaination needed for Stoichiometric problem and is Al salt colorless?

    Homework Statement The mass of element Q found in 1.00 mole of each of four different compounds is 38.0 grams, 57.0 grams, 76.0 grams, and 114 grams, respectively. A possible atomic weight of Q is a) 12.7 b 19.0 c 27.5 d 38.0 A solution is known to contain an inorganic salt of one of...
  50. W

    Formula of a mixed copper salt

    Homework Statement Cu2+OH-, and Br- form a mixed salt formula Cux(OH)yBrz. In an experiment to determine the values of x, y, and z in the formula of this compound, .760 g CuBr2 (223.4 g/mol) was dissolved in water and reacted with 10.22 ml 0.555M NaOH. Assume that in this reaction, all of...
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