Category: Chemistry Notes PPT

The carbon disulfide chemical formula is CS2. Carbon disulfide is also spelt as carbon disulphide. It is a colourless volatile liquid, which is used frequently as a building block in organic chemistry. Being the industrial and chemical non-polar solvent, the formula of carbon disulfide carries various chemical properties, which we will discuss on this page.

Along with this, we will have a look at the molecular formula of carbon disulfide, the structure to understand the carbon disulphide formula.

Formula of Carbon Disulfide

The carbon disulfide formula comprises the following chemical properties:

Properties of Carbon Disulfide

Carbon Disulfide Molecular Formula

The formula for carbon disulfide has the following molecular formula of carbon disulfide:

       

            

Carbon Disulfide Chemical Formula

The chemical formula for carbon disulfide carries the following thermochemistry properties:

Thermochemistry Properties of Carbon Disulfide          

Now, let’s have a look at the basic reaction for the carbon disulphide formula:

CS2 is a highly inflammable volatile liquid. Its combustion produces sulfur dioxide by reacting with atmospheric gas, i.e., oxygen. Therefore, according to the ideal stoichiometry, the following reaction undergoes:

CS2(l)    + 3 O2(g)    →   CO2(g) + 2 SO2(g)

Here, one mole of  CS2 reacts with three moles of O2  to produce CO2 and two moles of SO2.

Conclusion

CS2  is a highly reactive volatile liquid, which is formed as;

C   +   2S   →   CS2

Being a highly flammable gas, it must be stored in a refrigerator at lower temperatures.

Iron III oxide formula is the common primary formula that students come across while studying chemistry in many classes. In general, the use of the formula and the reactions that are associated with its progress, ranging from basic to more complex as the students advance from a lower class to higher classes. Iron (III) oxide, which is also known as ferric oxide, is an inorganic chemical compound. It is the primary iron oxide that is important and contains a mineral known as hematite, making it an important source of Iron. Sometimes, this compound is also known as either rust or hydrated ferric oxide.

Iron (III) Oxide Chemical Formula

Fe[_{2}]O[_{3}] is the chemical formula of Iron (III) oxide or the chemical name of Fe[_{2}]O[_{3}] is Iron III oxide. This is derived by taking the compound valency. In general, Oxygen (O) holds a valency of 2, and Iron (Fe) holds a valency of 3. When we write the chemical formula, it is a common process where the compounds usually exchange valencies to attain a balanced and neutral state. Thus, the valency of Oxygen goes to Iron and vice versa.

Iron (III) Oxide Structural Formula

Fe[_{2}]O[_{3}] may be obtained in multiple polymorphs. As the main one, α, Iron adopts an octahedral coordination geometry. It means each Fe center is bound to the six oxygen ligands. And, in the γ polymorph, a few of the Fe sits on tetrahedral sites, holding four oxygen ligands.

The structural formula of iron (III) oxide is represented as follows:

Preparation

Iron (III) oxide is the product of iron oxidation. It may be prepared in the laboratory by electrolyzing a sodium bicarbonate solution, an inert electrolyte, with an iron anode, which is represented chemically as:

4 Fe + 3 O[_{2}] + 2 H[_{2}]O → 4 FeO(OH)

The resulting hydrated iron (III) oxide, which is written here as FeO (OH), dehydrates around 200°C.

2FeO (OH) → Fe[_{2}]O[_{3}] + H[_{2}]O

This article mainly deals with the chemical formula of lithium oxide, the structural lithium oxide formula with its properties and uses. Lithium oxide is a white solid inorganic compound that is produced when lithium peroxide is decomposed at a temperature of 200 – 300 [^{0}]C. Also when the lithium metal is burnt in the air mixed with oxygen, lithium oxide is formed with small traces of lithium peroxide. Pure lithium oxide is also formed when lithium peroxide is decomposed at 450 [^{0}]C. Thus the chemical formula of lithium oxide is Li[_{2}]O. The other lithium oxide formula is commonly known as lithia or kickerite. It is a highly insoluble but thermally stable form of lithium. The perovskite structured oxides are highly electrically conductive in nature and are therefore widely used in the cathode of solid oxide fuel cells and oxygen generation systems. By analyzing the chemical formula of lithium oxide (Li[_{2}]O), it is clear that the bond shared between the two atoms of lithium and one atom of oxygen is ionic in nature as lithium being a metal of group 1 is highly electropositive while oxygen being group 16 element is highly electronegative in nature. Thus lithium [1s[^{2}]2s[^{1}]] has one valence electron in its outermost shell that is readily available to be donated to form a Li[^{+1}] ion. And oxygen [1s[^{2}] 2s[^{2}] 2p[^{4}]] can readily gain 2 electrons to complete its octane and form O[^{2-}] ion. Thus in Li[_{2}]O, two lithium-ions donate their outer shell electrons to oxygen that accepts two donated electrons to complete the utmost 2p subshell. Thus the ionic formula of lithium oxide will be 2[Li[^{+}]][O[^{2-}]]. This can be illustrated by the lewis dot structure of lithium oxide.

Lithium Oxide Structure

From the lithium oxide chemical formula (Li[_{2}]O) it has been observed that in the solid state, lithium oxides adopt an antifluorite structure that is relatable to calcium fluorite. Here in the calcium fluorite structure, the fluorine atoms are replaced with the lithium atoms, and the calcium atom is replaced by an oxygen atom. Thus the lithium oxide chemical formula demonstrates the four coordinated lithium ions [Li[^{+}]] as centers with eight coordinated oxides around the centers. In the ground state gaseous phase, lithium oxide shows a linear bond that is established on the basis of the strong electrostatic force of attraction between the atoms that are ionic in nature. According to the VESPER theory, the shape of the lithium oxide is bent which is similar to that of the water molecule. By the conventional electric deflection method, it has been found that the lithium oxide is non-polar in nature therefore the equilibrium bond angle between lithium and oxygen atoms is near about 180[^{0}]. According to the lithium oxide ionic formula, the coordinate geometry of lithium-ion [Li[^{2+}]] is tetrahedral whereas the oxygen ion [O[^{2-}]] is cubic in nature. The structural representation of the lithium oxide chemical formula is illustrated below.

The alternative schematic representation of the lithium-oxygen formula as a ball and stick model of their single unit cell is also illustrated below for a more clear understanding.

Lithium Oxide Properties

Lithium oxide is a white crystalline solid and the lithium oxide molar mass is equal to 29.88 g/mol. It has a density that is measured as 2.013 g/cm[^{3}]. It is a strong base with a pH value that is measured as 9.28, also known as log value, and is highly soluble in water and whenever it comes in contact with water while dissolving it reacts vigorously to form lithium hydroxide [LiOH]. It has a very high melting and boiling point. So the boiling point of lithium oxide is measured to be 2600 [^{0}]C whereas its melting point comes around 1438 [^{0}]C. It has an antifluorite structure with tetrahedral and cubical coordinate geometry for lithium and oxygen ions respectively. It has a refractive index measured at 1.644. It has a heat capacity of 1.8105 J/g K or 54.1 J/mol K. the standard molar entropy and the standard enthalpy of formation is measured as 37.88 J/mol K and -595.8 KJ/mol respectively with Gibbs free energy equals -562.1 KJ/mol.  

Lithium Oxide Uses

1. Lithium oxide when combined with copper exerts blue color and when mixed with cobalt generates pink color and therefore it is vastly used for the glazing of ceramics. But as lithium oxide reacts vigorously in water, therefore, it must be kept isolated from water.

2. In a thermal barrier coating system, lithium oxide is used for the evaluation of non-destructive emission spectroscopy as well as degradation monitoring in the system.

3. It is also added as a co-dopant with yttrium oxide which is a white solid and air-stable in nature also known as yttria as a topcoat for ceramic as it does not decrease easily and is therefore considered as a topcoat that sustains for a longer period of time.

4. At a very high heat lithium oxide emits a very definite pattern that is easily detectable and as the intensity of it increases the coating of lithium oxide decreases. But because of its spectroscopic nature of patter, its implantation allows the situ monitoring system thus enabling them to accurately predict the lifetime unless any major failure is involved.

5. It is used as a coolant in many nuclear plants and as a thickening agent to bring a certain consistency in greases. 

Aluminium trichloride or aluminium (III) chloride are other names for aluminium chloride. When aluminium and chlorine combine together, the chemical is created. AlCl3 is the chemical formula for it. When it comes to aesthetics, aluminium chloride is often white. It takes on a yellowish colour due to the presence of impurities (iron(III) chloride).

Aluminium chloride is used to make aluminium metal in industry, but it also has a variety of functions in the chemical industry, primarily as a Lewis acid. Covalently bound solid aluminium chloride (AlCl3) has a low melting and boiling temperature.

Here, we will study the molecular formula of aluminium chloride in detail.

Properties of Aluminium Chloride

Hans Christian Oersted, a Danish scientist, and chemist, discovered aluminium chloride for the first time in 1825. This is one of the earliest chemical compounds, notably in the field of organic chemistry. Below, we’ll go through a few properties of this compound.

• IUPAC Name-Aluminium Chloride

• Chemical formula of Aluminium Chloride- AlCl3

• Molar Mass-133.341 g/mol (anhydrous), 241.432 g/mol (hexahydrate)

• Density-  2.48 g/cm3 (anhydrous), 2.398 g/cm3 (hexahydrate)

• Melting Point- 192.6°C (anhydrous),100°C (hexahydrate, dec.)

• Boiling Point- 180°C

Preparation of AlCl3(Formula of Aluminium Chloride)

Aluminium chloride is primarily made by an exothermic reaction between two elements: aluminium and chlorine. Aluminium chloride can also be obtained in a variety of other methods. Reacting aluminium metal with hydrogen chloride or performing a single displacement reaction between copper chloride and aluminium metal are two popular methods. The following reactions show the preparation of  AlCl3(chemical formula of aluminium chloride).

2Al + 3Cl2 → 2AlCl3

2Al + 6HCl → 2AlCl3+  H2

2Al + 3CuCl2 → 2AlCl3 + 3Cu

Structure of Aluminium Chloride

It’s sometimes difficult to understand the structure of AlCl3. To write the structure first write down the formula of aluminium chloride. When this chemical molecule is subjected to different temperatures, it tends to create diverse types of structures. It also relies on the compound’s condition, whether it’s solid, liquid, or gaseous.

In its solid state, AlCl3 has a cubic close-packed layered structure. Its coordination geometry will be octahedral in this situation. In a liquid or molten form, aluminium chloride occurs as a dimer. Its coordination geometry will be tetrahedral in this case. The dimers disintegrate into trigonal planar at higher temperatures.

Physical Properties of Aluminium Chloride

• The melting and boiling points of aluminium chloride are quite low.

• At 180°C, it reaches its pinnacle.

• AlCl3 is a poor conductor of electricity in its molten state.

• Aluminum chloride is white in colour, but it is frequently contaminated by iron trichloride, which turns it yellow.

• Only at pressures more than 2.5 atm and temperatures more than 190°C can it become liquid.

Chemical Properties of Aluminium Chloride

• Aluminium chloride is an extremely potent Lewis acid.

• It’s a significant industrial catalyst.

• AlCl3 is a corrosive solid that is anhydrous, non-explosive, and non-flammable.

• When it comes into contact with water, it reacts strongly.

Applications of Aluminium Chloride

• Aluminium chloride is a versatile chemical molecule that may be used in a variety of applications, including chemical reactions and synthesis. The usage of aluminium chloride will be discussed further down.

• AlCl3 is primarily utilized as a catalyst in a variety of chemical processes. It is widely utilized in both acylations and alkylations in Friedel-Crafts reactions. It’s utilized in the process of making anthraquinone from phosgene and benzene.

• Aldehyde groups can be brought in or attached to aromatic series or rings using aluminium chloride. Consider the Gatterman-Koch reaction, in which a Lewis acid (aluminium chloride) is employed to extract a chloride ion from a solution.

• It’s also employed in light molecular weight hydrocarbon polymerization and isomerization procedures. Ethylbenzene manufacturing and dodecylbenzene production for detergents are two common examples.

• Bis(arene) metal complexes can be made by mixing aluminium chloride with aluminium and arene.

• Rubber, lubricants, wood preservatives, and paints are all made with aluminium chloride.

• Pesticides and medications contain it.

• As a flux in the melting of aluminium.

• It’s a type of antiperspirant.

Is Aluminium Chloride Hazardous?

Anhydrous aluminium chloride should be kept away from water and bases with extreme caution. Because of the intense heat of hydration, aluminium chloride can explode when it comes into contact with water. It also emits fumes into the atmosphere. During chemical reactions, protective equipment such as glasses, gloves, and a faceguard should be worn. This chemical component should be kept in a firmly sealed container that is kept dry.

• When AlCl3 comes into contact with moist air, it absorbs the moisture and becomes very acidic, turning into a sticky substance.

• Materials like stainless steel and rubber can be severely corroded by it.

• Long-term contact with this substance can irritate the skin, eyes, and respiratory tract.

• Aluminium chloride has been discovered to be a neurotoxic in some investigations, capable of destroying nerve tissues and causing lasting harm.

Conclusion

Aluminium chloride is also known as aluminium trichloride or aluminium (III) chloride. The chemical is formed when aluminium and chlorine are combined. The chemical formula for it is AlCl₃. Aluminium chloride is frequently white when it comes to aesthetics. Because of the presence of impurities (iron(III) chloride), it turns a yellowish colour.

Aluminium chloride is used in industry to create aluminium metal, but it also serves a variety of roles in the chemical industry, most notably as a Lewis acid. The melting and boiling temperatures of covalently bonded solid aluminium chloride (AlCl₃) are both low.

Acetylcholine Meaning

Acetylcholine (ACh) is an organic chemical that acts as a neurotransmitter in the brain and body of several animal types (including humans), a chemical message produced by nerve cells to send signals to other cells, such as neurons, muscle cells, and cells of the gland. Its name derives from its chemical structure: it is an acetic acid and choline ester. Sections of the body that use or are influenced by acetylcholine are considered cholinergic elements. Cholinergic and anticholinergics, respectively, are called substances that increase or decrease the overall cholinergic system function.

Not only the most common chemical messenger, but acetylcholine was also the very first neurotransmitter to be identified as well. It was discovered in 1914 by Henry Hallett Dale, and Otto Loewi later confirmed its existence. For their discovery, both individuals were awarded the 1936 Nobel Prize in Physiology/Medicine.

Acetylcholine Function

Acetylcholine Neurotransmitter

1. Acetylcholine is the parasympathetic nervous system’s chief neurotransmitter, a component of the autonomic nervous system (a peripheral nervous system branch) that contracts smooth muscles, dilates blood vessels, increases body secretions, and slows the heart rate. A response can be stimulated or blocked by acetylcholine and thus can have excitatory or inhibitory effects.

2. Acetylcholine is processed at the ends of cholinergic neurons (producing acetylcholine) in vesicles. In the peripheral nervous system, acetylcholine is released into the neuromuscular junction when a nerve impulse arrives at the terminal of a motor neuron. There, it interacts with a receptor molecule in a muscle fiber’s postsynaptic membrane (or end-plate membrane). This binding alters the membrane permeability, opening up channels that allow positively charged sodium ions to flow into the muscle cell (see the end-plate potential).

3. Sodium channels along the end-plate membrane become fully regulated as successive nerve impulses accumulate at a sufficiently high frequency, resulting in the contraction of muscle cells.

Role of Acetylcholine

1. A variety of body functions, including the cardiovascular system, are influenced by its movements within the autonomic nervous system, where it serves as a vasodilator, decreases heart rate, and decreases heart muscle contraction.

2.  It serves to increase peristalsis in the stomach and the amplitude of digestive contractions in the gastrointestinal system. Its operation reduces the bladder’s capacity in the urinary tract and increases voluntary voiding pressure.

3. It also impacts the respiratory system and activates all glands receiving parasympathetic nerve impulses to secrete. Acetylcholine tends to have several functions in the central nervous system.

4. Acetylcholine acts in the brain as a neurotransmitter and as a neuromodulator. There are a variety of cholinergic areas in the brain, each with different roles, such as playing an important role in excitement, concentration, memory, and motivation.

5. It is believed to play a major role in memory and learning, and in the brain of people with Alzheimer’s disease, it is in abnormally short supply.

Use of Acetylcholine in Medicine

In medicine, there are many uses to inhibit, hinder, or imitate the action of acetylcholine. Drugs that function on the acetylcholine system are either receptor agonists, activating the system, or inhibiting it with antagonists. The receptor agonists and antagonists of acetylcholine may either directly affect the receptors or indirectly exert their effects, e.g. by affecting the acetylcholinesterase enzyme that degrades the ligand-receptor. Agonists increase the activation level of the receptor, and antagonists decrease it. 

Owing to its multifaceted activity (non-selective) and rapid inactivation by choline, acetylcholine itself does not have therapeutic value as a drug for intravenous administration.

However, during cataract surgery, it is used in the form of eye drops to induce constriction of the pupil, which encourages rapid post-operational recovery.

Acetylcholine Effects

Disease and Disorders

Myasthenia gravis syndrome, characterized by muscle weakness and fatigue, occurs when the body improperly develops antibodies to the nicotinic receptors of acetylcholine and thereby prevents the proper transmission of acetylcholine signals. The motor end-plate is lost over time. Drugs that competitively inhibit acetylcholinesterase are successful in treating this condition (e.g., neostigmine, physostigmine, or especially pyridostigmine).

Do You Know?

Acetylcholine is synthesized from the compounds choline and acetyl-CoA by the enzyme choline acetyltransferase in some neurons. Cholinergic neurons have the capacity to generate ACh. An example of a central cholinergic area is the nucleus basalis of Meynert in the basal forebrain. The enzyme acetylcholinesterase converts acetylcholine into the inactive metabolites choline and acetate. In the synaptic cleft, this enzyme is abundant, and its role is important for proper muscle function in rapidly clearing free acetylcholine from the synapse. Some neurotoxins function by inhibiting acetylcholinesterase, thus leading to excess neuromuscular junction acetylcholine.

The simplest unsaturated aldehyde is acrolein (propenal in scientific terms). It’s a colourless liquid with an acrid, piercing odour. The scent of burnt fat is caused by glycerol in the burning fats breaking down into acroleins (similar to how the cooking oil is heated to its smoke point). It’s made in a factory from propylene and is mainly used as a biocide and a building block for other chemicals.

Production of Acrolein Sigma Aldrich

Industrially, acrolein is made by oxidising propene. Air is used as an oxygen source, and metal oxides are used as heterogeneous catalysts.

CH₂CHCH₃+O₂ → CH₂CHCHO + H₂O

This method produces around 500,000 tonnes of acrolein per year in North America, Europe, and Japan. Furthermore, the transient formation of acrolein is the source of all acrylic acid and helps in acrylic acid reaction. The primary difficulty is the competing overoxidation of this acid. Propane is a promising but challenging feedstock for the production of acrolein (and then acrolein to acrylic acid).

Here is the formation of Acrolein Sigma Aldrich:

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When heated to 280°C, glycerol (also known as glycerin) decomposes into acrolein:

(CH₂OH)₂CHOH → CH₂ = CHCHO + 2H₂O

When glycerol is produced to make biodiesel from vegetable oils or animal fats, this route is attractive. While glycerol dehydration has been demonstrated, it is not competitive with the petrochemical path.

Laboratory Methods for Producing Acroleins

Degussa developed the first industrial route to acrolein, which includes condensation of formaldehyde and acetaldehyde: 

HCHO + CHCHO → CH₂ = CHCHO+H₂O

On a lab scale, acrolein can be made by reacting potassium bisulfate with glycerol (glycerine).

Reactions Related to Acrolein

Since acrolein is a relatively electrophilic and reactive substance, it has high toxicity. It has a strong Michael acceptor, which explains why it reacts well with thiols. It readily forms acetals, one of which is the alkylidene pentaerythritol spirocycle derived from pentaerythritol. Also itself, acrolein participates in several Diels-Alder reactions. It is a precursor to commercial fragrances, such as lyral, norbornene-2-carboxaldehyde, and myrac aldehyde, through Diels-Alder reactions. Via the intermediacy of tetrahydro benzaldehyde, the monomer 3,4-epoxycyclohexylmethyl-3′,4′-epoxycyclohexane carboxylate is also generated from acrolein.

Furthermore, it helps produce critical chemical compounds, including methyl acrolein, poly acrolein, etc. Moreover, the production method and the reaction cost helps in determining the acrolein price.

Acrolein Uses

Biocide: 

Acrolein is primarily used as a contact herbicide in irrigation canals to combat submerged and floating weeds, as well as algae. It is used in irrigation and recirculating waters at a concentration of 10 ppm. It is used as a biocide in fracking waters and as a scavenger for hydrogen sulphide and mercaptans in the oil and gas industry.

Chemical Precursor:

Acrolein’s bifunctionality allows it to be used to make a variety of valuable compounds. The amino acid methionine is synthesised by combining methanethiol and Strecker synthesis. Methyl Pyridines are formed when acrolein condenses with acetaldehyde and amines. It is also considered an intermediate in the Skraup synthesis of quinolines, but it is rarely used due to its instability.

In the presence of oxygen and at concentrations greater than 22% in water, acrolein polymerises. The colour and texture of the polymer are affected by the environment. It will polymerise with itself over time, forming a transparent, yellow solid. It can turn into a rigid, brittle plastic when exposed to water.

In the preparation of biological specimens for electron microscopy, acrolein is often used as a fixative.

Health Risks Associated With Acrolein

Acrolein is a powerful irritant to the skin, eyes, and nasal passages and is harmful. The alkylation of glutathione is the primary metabolic pathway for acrolein. The WHO recommends a daily intake of 7.5 grammes of acrolein per kilogramme of body weight as a “tolerable oral acrolein intake.” At the same time, acrolein can be found in French fries (and other fried foods), only a few grammes per kilogramme. The Health Administration and US Occupational Safety have set an acceptable exposure limit of 0.1 ppm (0.25 mg/m³) at an eight-hour time-weighted average in response to occupational acrolein exposures.

Acrolein suppresses the immune system and may stimulate regulatory cells, preventing allergy development on the one hand but raising the risk of cancer on the other. One of the chemicals implicated in the toxic contamination of the Kim Kim River in 2019 has been identified as acrolein.

Analytical Methods

The “acrolein test” is used to determine if glycerin or fats are present. If the test is positive, a sample is heated with potassium bisulfate, and acrolein is released. When fat is heated to high temperatures in the presence of a dehydrating agent like potassium bisulfate (KHSO₄), the glycerol part of the molecule dehydrates, forming the unsaturated aldehyde acrolein (CH₂=CH-CHO), which has the odour of burnt cooking grease. There are more modern methods available.