Category: Chemistry Notes PPT

Aluminum is an element that has a symbol of Al. The atomic number of aluminum is 13. The density of this element is lower than those of other common metals. One can assume the density of this element to be one-third that of steel.

Aluminum has a great affinity towards other elements like oxygen. It also forms a protective layer of oxide on the surface when it is exposed to air. It should be noted that aluminum is similar to silver in its resemblance, which means that it is similar in color and has a great ability to reflect light.

Aluminum Formula

It is non-magnetic, ductile, and soft. There is one stable isotope of this element, which is 27Al. The isotope is very common. And according to experts, aluminum is the twelfth most common element in the Universe. The radioactivity of 26Al is also used in the form of radiodating.

It should be noted that aluminum is a weak metal in the boron group when it comes to the chemical formula of this element. Aluminum also forms compounds that are mainly in the oxidation state of +3. The cation of aluminum, which is Al³⁺, is highly charged and small. It is also polarizing and the bonds that aluminum forms are towards covalency.

Aluminum also forms a common association with oxygen in nature. This is in the form of oxides. Because of this reason, aluminum is found primarily on the rocks present on the crust on Earth. This element is the third most abundant element on Earth’s crust. It comes after silicon and oxygen. This element hardly ever occurs as a free metal. Students might be interested to note that the potash alum formula is KAI(SO₄)₂.12H₂O. There is also an aluminum hydroxide formula, which is called Al(OH)₃. Aluminum hydroxide is an inorganic salt used as an antacid. And the aluminum nitrate formula is Al(NO₃)₃. Aluminum nitrate is a white, water-soluble salt of aluminium and nitric acid.

Electronic Configuration of Aluminum

Students should remember that the electronic configuration of aluminum is 13Al = [Ne] 3s² 3p¹. There are other properties of aluminum that students should know about. For example, the chemical formula for aluminum is Al. The molecular weight of aluminum is 26.982 g / mol. The position of this element is in group 12, period -3, and p – block.

The density of aluminum is 2.70 g / cm³. The boiling point of Al is 2743 K. And there are three shells in this element. Electrons present per shell are 2, 8, and 3. The aluminum chloride formula is AlCl₃. Students should also learn the structure of aluminium chloride formula. The aluminum sulphate formula is Al₂(SO₄)₃. It is a good idea for students to learn the structure of aluminium sulphate formula.

Structural Formula for Aluminium Chloride: 

Structural Formula for Aluminium Sulphate:

The structural formula of aluminum is given below. The elements are arranged in the form of a face-centered cubic structure. Further, there is a specific uniqueness of this compound.

The formula for Argon Gas is Ar. It has the atomic number 18 and is a noble gas. The gas utilized in fluorescent tubes is monatomic argon. Argon Gas has the molecular formula Ar.

Argon is a non-combustible gas that is colourless and odourless. It has a higher density than air. When subjected to extreme heat or fire, the material will rupture violently. When it comes into touch with extremely cold water in its liquid form, it can produce intense boiling. As a food packing gas, it is quite significant.

Here, we will study the argon formula and molecular weight of argon/molecular mass of argon in detail.

Abundance and Properties of Argon Formula 

At 0.934 percent, argon is the third most abundant gas in the Earth’s atmosphere (9340 ppmv). It is more than twice as plentiful as water vapour (approximately 4000 ppmv on average, but fluctuates widely), 23 times as abundant as carbon dioxide (400 ppmv), and more than 500 times as abundant as neon (18 ppmv). Argon is the most abundant noble gas in the Earth’s crust, accounting for 0.00015 percent.

Argon gas formula – Ar

Molecular weight of Argon/molecular mass of Argon -39.948 g/mol

Density – 1.784 g/L

Boiling point – 185.848 °C

Melting point – 189.34 °C

Physical Properties of Argon

1. Argon is 2.5 times more soluble in water than nitrogen and has a similar solubility in water to oxygen. As a solid, liquid, or gas, argon is colourless, odourless, nonflammable, and harmless. Argon is chemically inert in most situations, and no stable compounds have been identified at ambient temperature.

2. Argon is a gas that is chemically inert.

3. When nitrogen isn’t inert enough, argon is the cheapest choice.

4. The heat conductivity of argon is very low.

5. For some applications, argon’s electrical properties (ionization and/or emission spectrum) are advantageous.

6. Other noble gases would work just as well in most of these applications, but argon is by far the most affordable. Because it exists naturally in the air and is easily obtained as a byproduct of cryogenic air separation in the manufacturing of liquid oxygen and liquid nitrogen: the principal constituents of air are employed on a big industrial scale, argon is affordable.

Applications of Argon Gas

1. Industrial Processes

Argon is employed in high-temperature industrial operations where non-reactive materials become reactive. In graphite electric furnaces, for example, an argon atmosphere is utilized to keep the graphite from burning.

The presence of nitrogen or oxygen gases in several of these processes may induce flaws in the material. Argon is utilized in gas metal arc welding and gas tungsten arc welding, as well as the processing of titanium and other reactive elements. Growing silicon and germanium crystals in an argon environment are also possible.

2. Preservative

To lengthen the shelf-life of the contents, argon is utilized to displace oxygen- and moisture-containing air in packing material (argon has the European food additive code E938). Airborne oxidation, hydrolysis, and other chemical reactions that break down the compounds are slowed or stopped completely. Argon is occasionally used to pack and seal high-purity chemicals and medications.

Argon is employed in winemaking for a variety of purposes, including providing a barrier against oxygen at the liquid surface, which can degrade wine by feeding both microbial metabolism (as with acetic acid bacteria) and conventional redox chemistry.

In aerosol cans, argon is sometimes employed as a propellant.

By displacing air to prepare a container for storage, argon is also employed as a preservative for materials like varnish, polyurethane, and paint.

3. Laboratory Equipments 

In Schlenk lines and glove boxes, argon can be utilized as an inert gas. In circumstances where nitrogen may react with the reagents or apparatus, argon is recommended over less expensive nitrogen.

Argon is the gas of choice for the plasma used in ICP spectroscopy and can be utilized as a carrier gas in gas chromatography and electrospray ionization mass spectrometry. For sputter coating specimens for scanning electron microscopy, argon is preferable. Argon gas is also extensively utilized in microfabrication for wafer cleaning and sputter deposition of thin coatings in microelectronics.

4. Medical Uses

Liquid argon is used in cryosurgery treatments such as cryoablation to destroy tissue such as cancer cells. It’s used in “argon-enhanced coagulation,” which is a type of argon plasma beam electrosurgery. The technique carries the risk of causing a gas embolism, and at least one patient has died as a result of it.

In surgery, blue argon lasers are used to repair eye abnormalities, weld arteries, and eliminate cancers.

Argon has also been used in experiments to replace nitrogen in the Argox breathing or decompression mix to expedite the removal of dissolved nitrogen from the bloodstream.

5. Miscellaneous Uses

Argon is utilized in energy-efficient windows as a thermal insulator. Argon is frequently used to inflate a dry suit in technical scuba diving because it is inert and has minimal thermal conductivity.

Safety

Although argon is non-toxic, it has a density of 38 percent that of air, making it a deadly asphyxiant in enclosed spaces. Because it is colourless, odourless, and tasteless, it is difficult to detect. The dangers of argon tank leaks in confined places are highlighted by a 1994 incident in which a man was asphyxiated after entering an argon-filled section of oil pipe under construction in Alaska, highlighting the importance of safe use, storage, and handling.

Conclusion

This article explains the formula for Argon Gas. It is a noble gas with an atomic number of 18. Monatomic argon is the gas used in fluorescence tubes. The molecular formula for Argon Gas is Ar.

Argon is a colourless and odourless noncombustible gas. Its density is higher than that of air. When exposed to severe heat or fire, the material will violently rupture. It can create strong boiling when it comes into contact with extremely cold water in its liquid form. It has a considerable impact as a food packaging gas.

Sodium nitrate is a chemical formula of white colour. It is an alkali metal nitrate as sodium belongs to the alkali Group I of the periodic table. A nitrate is any polyatomic ion made up of oxygen and nitrogen having a chemical formula NO[_{3}^{-}], which shows it as an anion. It is well known that sodium atoms donate one electron to form a cation, in order to achieve a stable electronic configuration. Hence, a cation of sodium and a polyatomic anion of nitrate combine with each other to form a neutral salt compound known as sodium nitrate and giving the sodium carbonate formula. Thus, the formula of sodium nitrate is given as NaNO[_{3}]. This is both the molecular formula of sodium nitrate and the chemical formula for sodium nitrate as is true for most other compounds. 

General Physical Properties of Sodium Nitrate

The salt of sodium nitrate is also known as Chile saltpetre, whose largest deposits, historically, have been mined in Chile and Peru. The names of the mineral forms of sodium nitrate are nitratine, nitrate or soda niter. The salt of sodium nitrate has the physical form of a white powder or as colourless crystals. 

The structural formula of sodium nitrate is given below showing the arrangement of the ions involved as in the answer to the question what is the chemical formula of sodium nitrate :

Some of the common physical properties of sodium nitrate are described below:

• The molecular weight of sodium nitrate as calculated from the sodium nitrate formula is 84.997 g/mol.

• It has a sweet odour.

• The density of sodium nitrate is 2.257 g/cm[^{3}]. 

• The melting point of sodium nitrate is 308 [^{0}]C and the boiling point is 380[^{0}]C.

• It is very much soluble in water, ammonia and hydrazine. It is slightly soluble in pyridine and insoluble in acetone since its an ionic compound as shown by the formula for sodium nitrate.

• The crystal structure of sodium nitrate is trigonal and rhombohedral. 

• The salt of sodium nitrate has the capacity to hold and retain water. 

Reactions and Uses

The industrial synthesis of sodium nitrate takes place by the neutralization of nitric acid with sodium carbonate or sodium bicarbonate. The reactions for this production methods are given below with the chemical formula of sodium nitrate and other compounds:

2HNO[_{3}] + Na[_{2}]CO[_{3}] → 2NaNO[_{3}] + H[_{2}]O + CO[_{2}]

HNO[_{3}] + NaHCO[_{3}] → NaNO[_{3}] H[_{2}]O + CO[_{2}]

Other methods also include the neutralization of nitric acid with sodium hydroxide or by the mixing of stoichiometric amounts of ammonium nitrate and sodium hydroxide, sodium bicarbonate or sodium carbonate. 

One of the most common uses of sodium nitrate is the industrial production of fertilizers, pyrotechnics, and smoke bombs, glass and pottery enamels, food preservatives and solid rocket propellant. This is because it has a readily available nitrate anion, as is clear from the chemical formula of sodium nitrate which is a useful component in several reactions that are involved in these industrial processes. 

Usually, refiners use sodium nitrate to make the hybrid aqua regia which is dissolved in gold and other different metals. It is also used for working with potassium nitrate and calcium nitrate for heat storage and for heat transfer in power plants that use solar energy for energy production. The wastewater treatment plants use sodium nitrate for the respiration of the facultative microorganisms. Nitrosomonas is a genus of specialized microorganisms, who consume nitrate preferentially over oxygen as it helps them to grow more rapidly in the treatment plants. 

The use of sodium nitrate also includes its use as a food additive and as a food preservative and colour fixative in the cured meats and poultry. 

On earth, Zinc Hydroxide exists as a rare natural mineral. It is also an amphoteric white solid compound, which has the ability to dissolve in a solution of strong acid or strong base. It takes place as three rare earth minerals Ashoverite, Wulfingite, and Sweetite. The formula for zinc hydroxide is Zn(OH)[_{2}].

Properties of Zinc Hydroxide

Physical Properties

Chemical Properties

Aluminium reacting with the zinc hydroxide solution gives a white precipitate that is soluble in excess of the reagent to produce complex Al(OH)[_{4}] indicates the aluminium presence. The respective zinc hydroxide to zinc oxide equation is given below:

2Al[_{3}]+(aq) + 3Zn(OH)[_{2}](aq) → 2Al(OH)[_{3}](s) + 3Zn

Zinc cations react with the hydrogen sulphide in the presence of ammonium chloride and ammonia produces a white precipitate of zinc sulphide, which is soluble in acids.

Zn[^{2+}](aq) + S[^{2-}] → ZnS(s)

Zinc Hydroxide Structural Formula

The zinc hydroxide chemical formula or chemical formula for zinc hydroxide is Zn(OH)[_{2}]. Let us look at the typical structural representation of Zinc Hydroxide is given below:

It exists in the tetragonal or orthorhombic forms.

In regular conditions, zinc dissociates to produce zinc ions along with the 2 hydroxide ions from the sodium hydroxide solution to produce zinc hydroxide.

Zn[^{2+}] + 2OH[^{-}] → Zn(OH)[_{2}]

When Zinc hydroxide reacts with an excess amount of sodium hydroxide, it precipitates to produce Zn (OH)[_{2}] and later dissolves into zincate ion.

Zn (OH)[_{2}] + 2OH[^{-}] → Zn(OH)[_{4}^{2-}]

Uses of Zinc Hydroxide – Zn(OH)[_{2}]

The primary uses of Zinc Hydroxide are listed below:

• It can be used as an adsorbing agent in medicine.

• They are utilized for the careful dressings where it works as a retentive. Huge bandages, which are utilized post-medical procedure, can be covered with the zinc compound for engrossing the blood from any injuries.

• It is also used as an intermediate for the commercial production of pigments and pesticides.

This article primarily deals with the structural and chemical formula of potassium hydroxide. Potassium hydroxide or as it is commonly termed caustic potash is one of the most important inorganic compounds and just like sodium hydroxide (NaOH), it is also a prototype strong base. Due to the basic and caustic properties, it has vast applications in the Industries. Potassium hydroxide is one of the most important and only prosecutor in many liquid soap solutions as well as many potassium-based chemicals. Therefore in 2005, the total production of potassium hydroxide was about 700,000 to 800,000 tons. Thus it is very important to learn the potassium hydroxide formula (known commonly as caustic potash formula). It is one of the organic compounds that is having a vast range of applications in almost all chemical industries. 

Chemical Formula of Potassium Hydroxide

The potassium hydroxide formula, commonly known as caustic potash formula is represented as KOH. It is predominantly an ionic compound. If the caustic potash formula is broken into two components with one hydroxyl anion [OH[^{-}]] that has a single negative charge on it and potassium ion [K[^{+}]] with one positive ion, thus the charge ratio becomes 1:1 and thus one potassium ion makes a stable bond with one hydroxyl ion. The synthesis of potassium hydroxide is very similar to that of sodium hydroxide in the industrial process which is known as the chloralkali process. The process follows the electrolysis of potassium chloride that produces potassium hydroxide, which is the chemical name of caustic potash with the release of chlorine gas as a by-product. Now by looking at the chemical formula of caustic potash that is KOH, the K-O bond is ionic due to the high electronegativity but the O-H bond in this case is covalent even when the electronegative difference is high. It is because after making the ionic bond by charge transfer with potassium, oxygen possesses more negative charge and as charge separation requires a lot of energy thus the ionization of H-O is not possible as the first ionization with K-O already happened. It is because the second ionization needs more energy for charge transfer than the first ionization due to high charge density. therefore, in the chemical formula for potassium hydroxide the K-O bond is ionic but the O-H bond is covalent.

Structural Formula of Potassium Hydroxide 

The KOH molecule in its solid-state crystallizes at a higher temperature and form a similar structure to NaCl. The KOH crystallizes in the monoclinic space group of C[_{2}^{2}]ーP2[_{1}]. The dimension of the two molecules in a molecular cell is a = 3.95, b = 4.00, c = 5.75, 𝛃 = 103.6[^{0}]. The OH[^{-}] ion is an effectively spherical anion whose radius is measured equal to 1.53 Å that falls between Cl[^{-}] and F[^{-}] cations. This spherical radius is due to the randomly or rapidly disordered hydroxyl ion. At room temperature, where the hydroxyl (OH[^{-}]) ion is completely in order the K[^{+}] ion centres are distorted, thus making the KOH bond length (depending on the orientation of hydroxyl ion) ranging from 2.69 to 2.15 Å. Also, each of the potassium ion centres is surrounded by an octahedron of oxygen atoms that are distorted. The oxygen atoms form a zigzag chain on the plane of the b-axis and according to the advanced stoichiometric arrangement the hydrogen atoms either lie on or nearby the zigzag chain of oxygen atoms that is very close or exactly linear in nature. Thus breaking of this hydrogen bond will lead to the formation of KOH cubic structure at high temperature. Therefore the molecular formula of potassium hydroxide is structurally represented as follows. 

The cubic structure of solid KOH is as follows.

Properties of Potassium Hydroxide

Some of the important physicochemical properties of KOH are listed below.

Uses

1. KOH is used as an electrolyte in all the alkaline batteries

2. By saponification, KOH is used for making solid as well as liquid soaps.

3. Many of the potassium salts that are used in many industrial purposes are manufactured by reacting KOH.

4. They are also used in chemical manufacturing, fertilizers production, petrochemical refining and cleansing solutions.