Weird Science: Salt Is Essential To Life
Table salt, sodium chloride , is a naturally occurring mineral essential for animal life. Salt is one of the most widely used and oldest forms of food seasoning . Saltiness is one of the five basic human tastes in addition to sweetness, sourness, bitterness, and umami . As salt dissolves in a solution or on food, it breaks into its component ions: sodium and chloride . The salty flavor primarily comes from the sodium ions.
Image courtesy of Dubravko Soric
SF Fig. 2.2. Individual sodium chloride table salt crystal as viewed under a powerful scanning electron microscope.
Image courtesy of Chhe
Salt plays a crucial role in maintaining human health. It is the main source of sodium and chloride ions in the human diet. Sodium is essential for nerve and muscle function and is involved in the regulation of fluids in the body. Sodium also plays a role in the bodys control of blood pressure and volume. Although sodium is essential, people who consume too much sodium may have hypertension or high blood pressure, a condition that can lead to serious illnesses such as heart disease, kidney disease, and stroke.
SF Fig. 2.3. A cow and her calf licking a cube of salt.
Image courtesy of Andrew Hayward from Wikipedia
SF Fig. 2.3. A wild herd of Indian bison, or gaur, at a natural salt lick, Rajiv Gandhi National Park, India.
Image courtesy of Amog Rajenderan from Wikipedia
What Is Sodium Used For
Sodium as a Heat Exchanger
Heat exchangers are devices that transfer heat from one place to another. Sodium is a commonly-found heat exchanger in nuclear power plants. Furthermore, its sodiums task to carry the heat from these plants reactors, to transfer it to a water supply which uses this heat to generate steam, and power electricity.
Using Sodium to Produce Other Materials
Sodium compounds are used to produce various materials. Firstly, theyre used to produce paper. In the paper-making process, sodium hydroxide treats/separates fibers in the pulling phase. Secondly, theyre used to produce clear glass. In this process, we heat sodium carbonate with calcium oxide. Thirdly, sodium compounds are used in creating different metals. For example, sodium combined with titanium tetrachloride produces titanium metal. In another reaction, sodium is a catalyst to create artificial rubber. Similarly, there are other materials which involve sodium in their production/usage.
The Element Sodium in Sodium-vapour Lamps
Sodium-vapour lamps generate a yellow, monochromatic glow, which illuminates streetlights. These lamps contain electrodes, metallic sodium, and forms of neon and argon. When current passes through the ionized neon and argon it vaporizes the metallic sodium, and the sodium ionizes to generate a shiny, yellow glow.
How Much Is Enough
Surprisingly little is known about how much salt we need. U.S. residents consume, on average, about 3,400 milligrams of salt per day. For decades, the U.S. government and organizations, such as the American Heart Association, have recommended people consume less salt. Current dietary guidelines recommend no more than 2,300 mg of sodiumabout a teaspoon of saltper day for teens and adults. No more than 1,500 mg per day is recommended for groups at higher risk of heart disease, including African Americans and everyone over the age of 50.
The U.S. dietary guidelines were established in the 1970s when relatively little information was available about dietary salt and health. The guidelines were the best guess, given the information available at the time. However, the guidelines made little difference in peoples behavior. Between 1957 and 2003, U.S. residents consumed, on average, 3,400 mg of salt per day.
Also, over the years, salt consumption remained steady, even though manufacturers added more salt to commercial foods. This consistency in salt intake suggests that people may somehow automatically regulate the amount of salt they eat. If that is true, does it mean people instinctively choose the right amount of salt? Or perhaps people used less salt at the table in an attempt to follow the new guidelines but unknowingly consumed more salt in their prepared foods.
Mike Ciesielski
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What To Expect During A Sodium Blood Test
A sodium blood test is sometimes just one part of a broader set of tests. You might hear your doctor or nurse call this a serum sodium test.
For the test, a technician will draw blood, usually from the inside of the elbow area or back of the hand.
The technician will tie an elastic band around your arm so your veins will swell, which makes drawing blood easier. They will then insert a needle into the vein, and blood will collect in a glass vial or a tube. Theyll untie the band on your arm. After the blood is collected, the technician will take out the needle and cover the puncture site.
The risks of the test are very low. You might bleed at the puncture site and have a bruise there later. Right after the blood draw, you might feel lightheaded. Infection is possible any time the skin is broken.
Atomic Number Of Sodium
Sodium is a chemical element with atomic number 11 which means there are 11 protons and 11 electrons in the atomic structure. The chemical symbol for Sodium is Na.
The atom consist of a small but massive nucleus surrounded by a cloud of rapidly moving electrons. The nucleus is composed of protons and neutrons. Total number of protons in the nucleus is called the atomic number of the atom and is given the symbol Z. The total electrical charge of the nucleus is therefore +Ze, where e equals to 1,602 x 10-19 coulombs. In a neutral atom there are as many electrons as protons moving about nucleus. It is the electrons that are responsible for the chemical bavavior of atoms, and which identify the various chemical elements.
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Dissolving Amphoteric Metals And Compounds
Strong bases attack aluminium. Sodium hydroxide reacts with aluminium and water to release hydrogen gas. The aluminium takes the oxygen atom from sodium hydroxide, which in turn takes the oxygen atom from the water, and releases the two hydrogen atoms. The reaction thus produces hydrogen gas and sodium aluminate. In this reaction, sodium hydroxide acts as an agent to make the solution alkaline, which aluminium can dissolve in.
- 2 Al + 2 NaOH + 2 H2O 2 NaAlO2 + 3 H2
Sodium aluminate is an inorganic chemical that is used as an effective source of aluminium hydroxide for many industrial and technical applications. Pure sodium aluminate is a white crystalline solid having a formula variously given as NaAlO2, Na2Al2O4. Formation of sodium tetrahydroxoaluminate or hydrated sodium aluminate is given by:
- 2 Al + 2 NaOH + 6 H2O 2 Na + 3 H2
This reaction can be useful in etching, removing anodizing, or converting a polished surface to a satin-like finish, but without further passivation such as anodizing or alodining the surface may become degraded, either under normal use or in severe atmospheric conditions.
Other amphoteric metals are zinc and lead which dissolve in concentrated sodium hydroxide solutions to give sodium zincate and sodium plumbate respectively.
Sodium And Water Aren’t Friends
O il and vinegar don’t mix. But sodium and water really don’t mix! Sodium reacts violently with water. The effect is fascinating.
When sodium metal is first placed into water, it floats. But it immediately begins to react with water, releasing hydrogen gas:
A great deal of energy is released in this reaction. It is enough to set fire to the hydrogen gas. The sodium metal reacts with water. So much heat is released that the sodium melts. It turns into a tiny ball of liquid sodium. At the same time, the sodium releases hydrogen from water. The hydrogen gas catches fire and causes the ball of sodium to go sizzling across the surface of the water.
Sodium reacts violently with water.
Sodium chloride can also be obtained from seawater and brine. Brine is similar to seawater, but it contains more dissolved salt. Removing sodium chloride from seawater or brine is easy.
Sodium stored in oil to prevent its reaction with the surrounding air.
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Characteristics And Properties Of Sodium
What properties are typical for sodium?
Sodium is an element in the 1 group of the 3 period of the Periodic Table. It is in the subgroup of alkaline metals NaO sodium oxide and NaOH sodium hydroxide display typical base properties. The most important natural compounds of sodium are table salt NaCl, Glaubers salt NaSO·10HO and sylvanite NaCl·KCl.
What Is Sodium Chloride
Sodium chloride is an ionic compound with the chemical formula NaCl.
Sodium chloride is also known as salt. It occurs in oceans and sea waters. It is also found as rock salt. About 1% to 5 % of seawater is made of NaCl. It is a crystalline solid, white. In its aqueous form, it is called a saline solution.
The molecular weight of NaCl is 58.44g/mol
This compound is water-soluble and consists of sodium cation and chloride anion. The sodium and chloride ions are present in the ratio of 1:1. It is widely known as table salt and is mostly used in the food industry for preservation and flavouring. The pH of sodium chloride is 7.
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Biological Role In Plants
In C4 plants, sodium is a micronutrient that aids metabolism, specifically in regeneration of phosphoenolpyruvate and synthesis of chlorophyll. In others, it substitutes for potassium in several roles, such as maintaining turgor pressure and aiding in the opening and closing of stomata. Excess sodium in the soil can limit the uptake of water by decreasing the water potential, which may result in plant wilting excess concentrations in the cytoplasm can lead to enzyme inhibition, which in turn causes necrosis and chlorosis.
In response, some plants have developed mechanisms to limit sodium uptake in the roots, to store it in cell vacuoles, and restrict salt transport from roots to leaves. Excess sodium may also be stored in old plant tissue, limiting the damage to new growth. Halophytes have adapted to be able to flourish in sodium rich environments.
Food Industry And Agriculture
Many microorganisms cannot live in a salty environment: water is drawn out of their cells by osmosis. For this reason salt is used to preserve some foods, such as bacon, fish, or cabbage.
Salt is added to food, either by the food producer or by the consumer, as a flavor enhancer, preservative, binder, fermentation-control additive, texture-control agent and color developer. The salt consumption in the food industry is subdivided, in descending order of consumption, into other food processing, meat packers, canning, baking, dairy and grain mill products. Salt is added to promote color development in bacon, ham and other processed meat products. As a preservative, salt inhibits the growth of bacteria. Salt acts as a binder in sausages to form a binding gel made up of meat, fat, and moisture. Salt also acts as a flavor enhancer and as a tenderizer.
Sodium chloride is used in veterinary medicine as emesis-causing agent. It is given as warm saturated solution. Emesis can also be caused by pharyngeal placement of small amount of plain salt or salt crystals.
Sodium chloride is used together with water as one of the primary solutions for intravenous therapy. Nasal spray often contains a saline solution.
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Sodium Metal In Nh3 Reduction Of Alkynes To Give Trans
Lets look at the first example: reduction of alkynes to trans–alkenes. Sodium will dissolve in liquid ammonia producing a beautiful deep blue color. When alkynes are present, they will be reduced to the trans alkene. This makes Na/NH3 a useful companion to the Lindlar reduction of alkynes, which gives cis–alkenes.
Reaction Of Sodium With Metals
When the surface of metallic sodium contacts mercury, an amalgam is formed an alloy of metal with mercury.
With potassium, the metal forms an alloy with the formula NaK. It is quite aggressive it may combust in air. If the content of potassium in the alloy varies from 40% to 90% in relation to sodium, the alloy remains liquid at room temperature.The sodium-potassium alloy NaK is obtained by alloying liquid potassium hydroxide KOH with melted metallic sodium. This reaction is carried out at a temperature of 400-450 C .
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Esterification And Transesterification Reagent
Sodium hydroxide is traditionally used in soap making . It was made in the nineteenth century for a hard surface rather than liquid product because it was easier to store and transport.
For the manufacture of biodiesel, sodium hydroxide is used as a catalyst for the transesterification of methanol and triglycerides. This only works with anhydrous sodium hydroxide, because combined with water the fat would turn into soap, which would be tainted with methanol. NaOH is used more often than potassium hydroxide because it is cheaper and a smaller quantity is needed. Due to production costs, NaOH, which is produced using common salt is cheaper than potassium hydroxide.
Biological Role In Humans
In humans, sodium is an essential mineral that regulates blood volume, blood pressure, osmotic equilibrium and pH. The minimum physiological requirement for sodium is estimated to range from about 120 milligrams per day in newborns to 500 milligrams per day over the age of 10.
Diet
Sodium chloride is the principal source of sodium in the diet, and is used as seasoning and preservative in such commodities as pickled preserves and jerky for Americans, most sodium chloride comes from processed foods. Other sources of sodium are its natural occurrence in food and such food additives as monosodium glutamate , sodium nitrite, sodium saccharin, baking soda , and sodium benzoate.
The U.S. Institute of Medicine set its tolerable upper intake level for sodium at 2.3 grams per day, but the average person in the United States consumes 3.4 grams per day. The American Heart Association recommends no more than 1.5 g of sodium per day.
High sodium consumption
High sodium consumption is unhealthy, and can lead to alteration in the mechanical performance of the heart. High sodium consumption is also associated with chronic kidney disease, high blood pressure, cardiovascular diseases, and stroke.
High blood pressure
Hypertension causes 7.6 million premature deaths worldwide each year.
Physiology
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Salient Features Of Sodium
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Following are the major features of sodium element
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Sodium metal a soft element that be can be easily cut with a knife.
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Sodium is a good conductor of heat and electricity.
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Because of having low atomic mass and large atomic radius, sodium is one of the least dense elements .
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Sodium can float on water.
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Sodium along its compounds glow yellow .
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Sodium compounds have very high commercial importance and have high demand in the industries of glass, paper, soap, and textiles.
Reaction Of Sodium With Bases
Sodium metal reacts rapidly with water to form a colourless basic solution of sodium hydroxide and hydrogen gas . The reaction continues even when the solution becomes basic. The resulting solution is basic because of the dissolved hydroxide. The reaction is exothermic. During the reaction, the sodium metal may well become so hot that it catches fire and burns with a characteristic orange colour. The reaction is slower than that of potassium , but faster than that of lithium . As the reaction continues, the concentration of hydroxide increases.
2Na + 2H2O 2NaOH + H2
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The Element Sodium In Our Bodies
The element sodium is extremely vital for our bodies. It acts as an electrolyte and mineral that regulates the fluid in our cells. Sodium also maintains our nerve functions, muscle movement, and electrolyte balance. Moreover, this sodium enters our bodies through consuming foodstuffs, and it exits in the form of perspiration/urination. During this cycle, our blood/lymph fluids store the sodium. Furthermore, if this sodium reaches unhealthy levels, then our bodies react to this change sometimes, in the form of diarrhea, malnutrition, or hyponatremia/hypernatremia. Hence, its very important that we monitor our bodys sodium levels by regulating our diets.
Density Pressure And Temperature
The density of a material varies with temperature and pressure. This variation is typically small for solids and liquids but much greater for gases. Most materials expand when their temperatures increase. Rising temperatures make the liquid expand in a liquid-in-tube thermometer and bend bimetallic strips. As a result of this expansion, the density of most materials decreases. This effect is caused by a decrease in the atomic number density. This dependence is usually expressed by the coefficient of linear or volume expansion.
Increasing the pressure on an material decreases the volume of the object and thus increases its density via the atomic number density. Compressibility change.
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Symptoms Of Sodium Imbalance
You might have certain symptoms that lead your doctor to suspect that your sodium level may be too high or too low. You might be confused, forgetful, or have problems with reasoning. Other symptoms your doctor may watch for include:
- Kidney problems
Your doctor might order a test if youre showing signs of a sodium imbalance or are at risk of becoming imbalanced.
Sodium And Ammonia Reaction
Sodium reacts with ammonia gas to form sodamide and hydrogen gas. In this reaction, liquefied ammonia is typically used to prepare sodamide. The chemical equation for preparing sodamide is given below.
2Na + 2NH3 2NaNH2 + H2
This is an example of a redox reaction. Sodamide is also referred to as sodium amide and sodium azanide.
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