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

    The Salt Industry: Benefits & Limitations on Life & Society

    Salt industry What is the industry? What chemistry is involved? Process… What products come from this process/industry? Where do the products go? Who uses them? For what do people use them? Evaluate benefits of this industry on life and society How has this production benefited...
  2. E

    Discover the Color of Solid Silver Phosphate: Analysis and Facts

    What is the color of solid silver phosphate? I don't have a reference book handy with me. Thanks.
  3. B

    Can Radio Waves Turn Salt Water into Fuel?

    Here's the link: http://www.popsci.com/scitech/article/2007-11/turning-water-fuel I find the idea interesting that the radio waves may assist in breaking the oxygen-hydrogen bonds of the water molecule. But, why should this effect only exist with salt water and not pure water? Salt water is...
  4. P

    Salt's Effect on Ice Melting Temperature: Investigating Latent Heat Absorption

    When salt is added to a ice water solution it makes the ice melt at a colder temperture than zero degrees C. I'm told because it weakens the bonds that hold the ice together. Is the latent heat asorbed by the melting ice at the new lower temperture the same as if the salt was not added and...
  5. T

    Fueling the Body: My Love Affair with Salt

    I'm one of those rare people who eats to fuel my body. I'm usually done eating before everyone else has finished praying. Flavor was never a big deal to me for the most part, so I never, ever, reach for the salt and pepper shakers. I always thought of them as something to use to cover bad...
  6. S

    Liquid-fuel molten salt reactor?

    I've run into a some advocates (assorted nuclear engineers and grad students it seems) for an unusual nuclear reactor design. It is a thermal-spectrum thorium breeder reactor. The fuel is liquid - it is a molten salt, containing the fluorides of both U-233 fuel and thorium, as well as lithium...
  7. F

    Fresh vs. Salt Water: Unmixable Conditions Explained

    oceanic water obviously has a higher salt concentration and is more dense than fresh water. What specific conditions keep these two from mixing? On discovery, I see underwater caves where salty and fresh waters don't mix. What's behind this? Should we integrate their schools?
  8. F

    If you add salt to liquid nitrogen,would it turn into a superconductor?

    I was wondering also if you put a magnet above it, then lifted the magnet up,would the nitrogen and salt come up too?
  9. K

    Potenital Differnce between Salt Bridge and rxn

    Homework Statement A 0.100 M solution of sodium palmitate (C15H31COONa) is separated from a 0.200 M NaCl solution by a membrane barrier that is permeable to Na+ and Cl-, but not to palmitate ions. I need to calculate the concentrations of the ions on both sides of the barrier once...
  10. G

    Separating salt and sodium carbonate help

    Homework Statement Given a mixture of salt and sodium carbonate, how could you determine the amount of sodium carbonate in the mixture?Homework Equations The Attempt at a Solution Salt and sodium carbonate are both soluble, so I would I use HCl to react with the Na2CO3 leaving the NaCl H20 and...
  11. S

    Salt crystal forms after 3 days of evaporation

    If a salt crystal forms after 3 days of evaporation, and the crystal mass is 30 mg, how many Na+ and Cl- ions was added to the crystal each second (average). How do I solve this?
  12. E

    High-power electricity through Salt Water

    Hello all, How strong a current can I move though water? Googling I have found only conductivity of salt water, but what is water's impedance? Can I create 1 ms pulse of 500 volts and 1 A using salt water? I want to use salt water as electrodes: two metal electrodes submerged in two...
  13. T

    Salt Crystals: Do Negative Ions Emit?

    I'm not sure where this question belongs, maybe in chemistry? move it if necessary. so the quest is this I have a salt crystal lamp. it is a large block of salt on a wood base with a light bulb inside a hollow in the salt. the selling point of these lamps is that the heat from the...
  14. Y

    Why densities of pure and salt water are different

    Density = mass/volume (D=m/v), explain the difference in density of pure & salt water in words and using a mathematically based example
  15. R

    I want to resolve to the degree of saturation of a salt solution

    I want to measure salt brines. I can measure specific gravity and degrees Fahrenheit. I need a formula that I can insert the two measured values into and get the degree of saturation of my brine. I can't find a formula. I'm not sure a formula exists, but I can't understand why not. There are...
  16. Greg Bernhardt

    Medical Epsom Salt Baths: My Experience Training for Soccer

    I'm currently training hard for a top amateur soccer team in my area. After a few training sessions my muscles are destroyed. I have severe DOMS (delayed onset muscle syndome). I was reading some online material about Epsom salts (magnesium sulfate) and how they claim to relieve muscle pain...
  17. H

    What is a linear salt gradient?

    Can anyone tell me what a linear salt gradient is?
  18. A

    Salt Water Connection: Bridging Circuits with Water for Rube Goldberg Projects

    I am trying to include salt water in my Rube Goldberg project. Instead of the wires that connect a motor simply being continuous, I want to bridge a connection through salt water. Meaning, but one wire, put both ends in the solution so that the connection still works. But its not working. Are...
  19. T

    How do I determine volume of salt water mixture before mixing?

    I read that when salt and water are mixed that the overall volume decreases by 2.5% (I'm not sure if this is relative to the original volume of the water or both the water and the salt). I'm not sure why this is the case and am interested in that. Moreover, I'd like to know how one would...
  20. K

    Why Does Na2CO3 Result in a Basic Solution in Water?

    Homework Statement Explain why Na2CO3 gives a basic solution when dissolved in water. The Attempt at a Solution The cation is Na+ while the anion is CO32-. The cation has no affinity for neither protons nor hydroxide ions. The anion should have basic properties to make a basic...
  21. C

    Is there a way? Salt Water to Fresh Water

    Any one know of a machine/chemical to convert Salt water (8.8lb-9.4lb) to Fresh water (8.6lb) on a LARGE scale?? I have read several things on converting using the sun to evaporate the water, but that's only like a liter a day. I would love to find something or have something made that would...
  22. M

    Radio Wave Separation of H2O from Salt Water: Q&A

    Not sure if I'm in the right forum, but does anyone know anything about the mechanism behind using radio waves to disassociate hydrogen and oxygen atoms from salt water?
  23. S

    Density of salt and graphs

    Can anyone tell me what the density of salt is on average? I know there are many types of salt, but there must be an average value to this right? Because I’ve got the volume of this salt particle and I need its density in order to work out the mass. I also want to plot a graph of Intensity...
  24. S

    Calculating Mie Scattering of Salt Particles

    Hello, can anyone tell me the equation to the Mie scattering. I have salt particles of a specific size, and I want to work out the Mie scattering of it. Thanks a lot From steve.
  25. M

    Why does salt and ethanol affect CO2 production in fermentation?

    Why does salt and ethanol affect carbon dioxide production in the fermentation process of sucrose? Is it because the yeast has to break the sugar down by hydrolysis and that ethanol and salt are soluble, thus, in 'competition' with the yeast because they are occupying needed water molecules...
  26. R

    Deriving the cooridinate numbers of both ions in rock salt

    How would I go about deriving the cooridinate numbers of both ions in rock salt, and, how could I account for the differences in lattice enthalpy between the following; LiCl (861 kJ/mole) - NaCl (787) LiCl - LiF (1046) LiCl - MgO (3850) Cheers.
  27. J

    Questions on salt water vs fresh water

    Questions on salt water vs fresh water... I live in an area that is experiencing a long drought. So, I got to thinking about the differences in fresh and salt water and have a few questions that I'd like your thoughts on. Just what happens to salt in salt water? Do the molecules of water and...
  28. T

    Why Does Salt Water Taste Salty?

    Homework Statement If NaCl dissociates into Na+ and Cl- ions when dissolved in water, why does the solution still taste salty? Homework Equations None The Attempt at a Solution I think its because a chemical change hasn't happened. Am I right? Can someone go into a bit more detail...
  29. T

    Optimizing Salt Bridge Conductivity in Voltaic Cells

    Iam doing an experiment on voltaic cells in particular Iam studying the effect that the thickness of the salt bridge has on the emf of the cell over time. iam thinking that the thicker the salt bridge the longer it will last. I think that will happen because maybe there is more surface area...
  30. hagopbul

    DPPH (a chemical salt [(C6H5)2N-NC6H2 (NO2)3]) and EPR/ESR

    I am doing this test on DPPH (a chemical salt [(C6H5)2N-NC6H2 (NO2)3]) The goal of the experiment is to study The Electron Paramagnetic Resonance or The Electron Spin Resonance Buy using this way: see it in the file
  31. L

    Unlocking the Power of Salt Water: Harnessing Hydrogen & Oxygen

    This article; http://www.shns.com/shns/g_index2.cfm?action=detail&pk=SALTASFUEL-09-10-07 , from Scripps Howard talks about what appears to be a new method for seperating Water into Hydrogen and Oxygen by exposing it to an RF generator. From the Article: The article seems to make a big...
  32. baywax

    Radio Frequencies Help Burn Salt Water

    Hello good members and guests of PhysicsForums. Whats the deal with this? Are we going to be fueling vehicles with sea water now? http://green.yahoo.com/index.php?q=node/1570
  33. Evo

    Burning Salt Water: The Future of Fuel?

    Does anyone think anything will come from this? http://news.yahoo.com/s/ap/20070910/ap_on_sc/burning_seawater
  34. P

    What is the Percent of Salt by Weight in Mono Lake at Different Water Levels?

    High School Geometry Homework Statement When the concentration of salt in a lake is greater than three percent by weight, the lake is a salt lake. Find the percent of salt by weight for each of the water levels of Mono Lake Shown in the table. One liter of water weighs 1kg or 1000 grams...
  35. T

    Reciprocal Salt Pairs: What Does It Mean?

    I understand that NaCl and NH4HCO3 are reciprocal salt pairs. What does this mean?
  36. S

    Can u rust a magnet using vinegar and salt water in a reasonable time?

    I have designed a science experiment for my project in which i see whether a magnet gets weaker when it rusts. So, i take a magnet that is not rusted and see how many paper clips it can pick it up. Then, i rust it and see how many paperclips it can pick up after that. I need to finish this...
  37. A

    Molten Salt: Disassociation or Vibration?

    Generally, when you melt a salt (CaCl2 @800deg C specifically) are the ions disassociated as in a solution or is molecular vibration simply great enough to not allow the formation of intermolecular bonds and the atoms are floating around still paired? This is probably a dumb question and my...
  38. A

    Platinum Oxidation in Molten Salt Reactor

    In an argon atmosphere, there is a pure platinum crucible that is used to heat Calcium Chloride salts to 850 deg C. After it is heated, pure chlorine gas is bubbled through the molten salt to remove CaO impurities. The heating method is by induction heating. My questions/concerns: Since we...
  39. F

    What are the requirements for preparing an insoluble salt?

    In order to prepare an insoluble salt, there must only be a solid present right? The rest must be soluble and in aqueous state right?
  40. W

    Copper Wire as a Salt Bridge: The Mystery of its Function in Voltaic Cells

    in a recent chemistry experiment at school, two voltaic (galvanic) cells were set up with the same solutions in either beaker (one being Copper Sulfate, and the other was another metal solution) anyway, one had a potassium nitrate salt bridge, the other a copper wire salt bridge... sooooooooooo...
  41. S

    Solving a Linear System for Two Tank Salt Solution Problem

    For this problem I don't think I am setting up the linear system right: Two tanks containing 500 gal of salt solution. Pure water pours into the top tank @ 5gal/s. Salt solution pours out of the bottom of the tank and into the tank bellow @ 5 gal/s. There is a drain @ the bottom of the second...
  42. T

    Exploring the Non-Reactivity of Magnesium Nitrate with Sulphuric Acid

    why magnesium nitrate does not react with sulphuric acid?:confused: can somebody help answering? thank you.:smile:
  43. T

    Salt Crystals: Shape & Structure

    What is the shape of salt crystals.??
  44. L

    Salt Tank - Differential Equation

    This problem has been perplexing me all week, it doesn't look hard but somehow I can't get the right answer. The question is - A salt tank of capacity 500 gallons contains 200 gallons of water and 100 gallons of salt. Water is pumped into the tank at 3 gallon/min with salt of 1 lb/gallon...
  45. P

    Does salt added to water decrease the time needed to reach boiling point?

    I'm not sure if this would be better in another thread of not but here I go... I have heard that if you put salt into water it will make it boil faster. Several people have also told me they read this same statement in cooking magazines and what not. Not wanting to trust a cooking magazine...
  46. F

    Help Solve Chemistry Lab Questions on Delta G, H & S

    Well, today in my chemistry lab, my teacher let us out early without getting the class to answer a few questions, and now I'm stuck on my lab report! We were supposed to have a class discussion, but we didn't. I was wondering if anyone knew how to answer the following questions: If delta G...
  47. S

    Calculating Ksp of salt (answer check)

    69. Calculate the Ksp for each of the salts whose solubility is listed below. a) CaSO4 = 3.3 x 10-3 mol/L b) MgF2 = 2.7 x 10-3 mol/L Answers: a) Solution 1. Write the dissociation reaction and the Ksp expression for the equilibrium reaction. Thus, CaSO4(s) <---> Ca2+ (aq) + SO42-...
  48. H

    Melting Points of Iron Oxide, Aluminum, Baking Soda, Table Salt & Gas Stove Heat

    hello there about wat temp does ,Iron oxide, aluminum, baking soda, table salt melt? degress F please. and about how hot does a US conventional gas stove get? thanks. and aluminum foil is pure aluminum right?
  49. S

    Which Salt Produces Lowest pH Solution?

    Which one of the following salts, when dissolved in water, produces the solution with the lowest pH? a.NaCl b.NH4Cl c.MgCl2 d.AlCl3 Ammonium chloride My answer lies with b or d since they are both acidic salts, but I think is it d since the K_a is greater...
  50. B

    Will Salt help cool a cars radiator?

    Today while sitting parked in my FIL's van, the one I just put a new thermostat in, but failed to really test to see if it would overheat? A couple miles down the road, it pegs the temp guage. I put the OEM of 192* instead of 160* because it wasnt passing smog, they said the computer this/that...
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