[Chemistry Class Notes] on Anthracite Pdf for Exam

Strong coal, also known as anthracite, is hard, compact coal with a submetallic lustre. It is the highest rating of coals because it has the highest carbon content, the fewest impurities, and the highest energy density of all grades of coal.

Anthracite is the most metamorphosed coal (though it still reflects low-grade metamorphism), with a carbon content ranging from 86 to 98 percent. The term refers to coal varieties that do not produce tarry or other hydrocarbon vapours when heated below their ignition stage. Anthracite is difficult to ignite and produces a brief, blue, smokeless flame.

Structure of Anthracite Coal

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Composition of Anthracite Coal

Classification of Anthracite

Standard grade anthracite is used primarily in power generation, whereas high grade (HG) and ultra high grade (UHG) anthracite are used primarily in the metallurgy industry. Just a few countries around the world mine anthracite, which makes up about 1% of global coal reserves. China produces the bulk of the world’s soybeans; other suppliers include Russia, Ukraine, North Korea, South Africa, Vietnam, the United Kingdom, Australia, Canada, and the United States. In 2010, total production was 670 million tonnes. Anthracite is divided into three groups based on the amount of carbon it contains. Standard grade is used as a domestic fuel and in the production of industrial power. The purer higher grades of anthracite are used in steelmaking and other metallurgical industries because they are purer (i.e., they have a higher carbon content). The following are the technical characteristics of different grades of anthracite:

High-Grade Forms of Anthracite

The highest grades of anthracite coal are high grade (HG) and ultra high grade (UHG). They are the purest types of coal, with the highest degree of coalification, carbon count, and energy content, as well as the fewest impurities (moisture, ash and volatiles).

High grade and ultra high-grade anthracite are tougher and have a higher relative density than normal grade anthracite. C240H90O4NS, which represents 94 percent biomass, is an example of a chemical formula for high-grade anthracite. The carbon content of UHG anthracite is usually about 95%.

They are also used in metallurgy as a cost-effective replacement for coke in processes such as sintering and pelletizing, as well as pulverised coal injection (PCI) and direct injection into blast furnaces, as opposed to standard grade anthracite (used primarily for power generation). They can also be used to purify water and as a smokeless fuel in the home.

The overall anthracite industry is made up of just a small proportion of HG and UHG anthracite. Russia, Ukraine, Vietnam, South Africa, and the United States are the main producers.

Terms Related to Anthracite

Anthracite comes from the Greek word anthrakts, which means “coal-like.” Black coal, hard coal, stone coal, dark coal, coffee coal, blind coal (in Scotland), Kilkenny coal (in Ireland), crow coal or craw coal, and black diamond are other names for anthracite. The word “Blue Coal” refers to a once-popular and trademarked brand of anthracite mined by the Glen Alden Coal Company in Pennsylvania and dyed blue at the mine before being shipped to northeastern U.S. markets to differentiate it from its rivals.

In British and American English, the word culm has different connotations. The imperfect anthracite of north Devon and Cornwall, which was used as a dye, is known as “culm” in British English. Some Carboniferous rock strata found in both Britain and the Rhenish hill countries are often referred to by this name (the Culm Measures). Finally, it may apply to coal exported from the United Kingdom in the nineteenth century. The waste or slack from anthracite mining, often dust and small parts not suitable for use in home furnaces, is referred to as “culm” in American English.

How is Anthracite Different From Bituminous?

Anthracite differs from ordinary bituminous coal in that it has a higher hardness (2.75–3), a higher relative density of 1.3–1.4, and a semi-metallic lustre with a mildly brown reflection. It has a high proportion of fixed carbon and a low proportion of volatile carbon. It’s also free of any soft or fibrous notches, and it doesn’t soil your fingers when you rub it. The transformation of bituminous coal into anthracite is known as anthracitization.

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Features of Anthracite

  • Freshly mined anthracite usually has a moisture content of less than 15%. On a moist, mineral-matter-free basis.

  • The heat content of anthracite varies from 26 to 33 MJ/kg (22 to 28 million Btu/short tonne). On an as-received basis, the heat content of anthracite coal consumed in the United States averages 29 MJ/kg (25 million Btu/ton) (i.e., containing both inherent moisture and mineral matter). 

  • Density of anthracite is 1.3-1.8 g/cm3.

  • The hardness of anthracite on the Mohs scale is 2.2-3.8.

  • The moisture content of anthracite coal is 0.5-4%.

  • The pH of a water suspension of anthracite is 7-7.8.

  • Volatile content is 0.5-20% in anthracite.

  • The resistivity of anthracite is 1×10−3 to 2×105 Ω-m.

  • Anthracite refuse or mine waste has been used for coal power generation as a method of recycling since the 1980s.

Anthracite is a chemical intermediate between ordinary bituminous coal and graphite, formed by the more or less complete removal of the volatile constituents of the former, and it is most abundant in areas subjected to significant stresses and pressures, such as the flanks of large mountain ranges. Anthracite is associated with highly deformed sedimentary rocks exposed to higher pressures and temperatures (but not metamorphic conditions), whereas bituminous coal is associated with less deformed or flat-lying sedimentary rocks.

Deep mined compressed layers of anthracite in the folded Ridge and Valley Province of the Appalachian Mountains of East-central Pennsylvania, for example, are extensions of the same layers of bituminous coal. These are mined on the Allegheny Plateau of Kentucky and West Virginia, Eastern Ohio, and Western Pennsylvania, where the sedimentary rocks are mostly smooth and undeformed. Similarly, South Wales’ anthracite area is limited to the twisted section west of Swansea and Lanelle, with the central and eastern parts supplying steam coal, coking coal, and domestic house coals.

Anthracite’s structure has been altered by the formation of secondary divisional planes and fissures, making the initial str
atification lines difficult to see. The thermal conductivity is also higher; when kept in the warm hand, a lump of anthracite feels noticeably colder than a comparable lump of bituminous coal at the same temperature. In the article coal, the chemical composition of some common anthracites is given. Anthracite resembles a mineraloid jet in appearance and is often used as a jet substitute.

Use of Anthracite Coal

  • Today, anthracite is primarily used as a domestic fuel in hand-fired stoves or automatic stoker furnaces. Therefore, it is known as anthracite domestic fuel. It provides a lot of energy for its weight and burns cleanly with little soot, so it’s perfect for this. Its high cost renders it unsuitable for use in power plants. 

  • The fine particles are often used as filter media and as a component in charcoal briquettes. 

  • According to the United Kingdom’s Clean Air Act of 1993, anthracite was an approved fuel that could be used within a specified Smoke Control Area, such as the central London boroughs.

Reserves of Anthracite

Russia, China, and Ukraine have the largest estimated recoverable anthracite reserves among current producers. Vietnam and North Korea are two other countries with significant reserves.

The Lackawant to Coal Mine in northeastern Pennsylvania, United States, in and around Scranton, Pennsylvania, is home to the world’s largest and most concentrated anthracite deposit. The deposit, known locally as the Coal Region, spans 480 square miles (1,200 square kilometres) of coal-bearing rock that once contained 22.8 billion short tonnes (20.68 billion tonnes) of anthracite. The geographical area is approximately 100 miles (161 kilometres) long and 30 miles (48 kilometres) wide. It is estimated that 7 billion short tonnes (6.3 billion tonnes) of mineable reserves remain due to historical mining and growth of the lands overlying the coal. Smaller anthracite deposits, such as those traditionally mined in Crested Butte, Colorado, can also be found in the United States.

The Groundhog Anthracite Deposit is the world’s largest previously undeveloped anthracite deposit, found in British Columbia, Canada. It is owned by Atrum Coal, an Australian publicly traded corporation with 1.57 billion tonnes of high-grade anthracite.

Anthracites from the Tertiary or Cretaceous period have been discovered in the Crowsnest Pass region of the Rocky Mountains in Canada, as well as in the Andes of Peru.

Different Forms of Anthracite Fuel

Burnglo Anthracite Smokeless Fuel

Burnglo Anthracite Smokeless Fuel is a great value for money standard grade coal that’s ideal for smoke control areas. It produces a decent amount of heat over a long period of time and has a low, blue flame. Customers that use Burnglo Anthracite Smokeless Fuel in closed appliances such as room heaters, glass-fronted stoves, boilers, and cookers love it.

Anthracite Beans

Anthracite Beans are uniformly sized bits of high-grade coal that burn cleanly. They produce a lot of heat and burn with a low flame for a long time. Anthracite Beans produce little compact ash, making them ideal for use in gravity and hopper-fed boilers.

Anthracite Grains

Anthracite Grains are smaller, evenly sized pieces of coal with a long fire life and high heat production than Anthracite Beans. Anthracite Grains are used in gravity and hopper fed boilers to produce low, compact ash. 

Mining Sites of Anthracite

China currently mines the vast majority of the world’s anthracite, accounting for more than three-quarters of total production. The majority of anthracite produced in China is of standard grade, which is used in power generation. Increased demand in China has turned the country into a net importer of the fuel, primarily from Vietnam, another major producer of anthracite for power generation, though Vietnam’s exports may be curtailed due to rising domestic consumption.

Anthracite production in the United States is currently about 5 million tonnes per year. The state of Pennsylvania mined about 1.8 million tonnes of that total. Anthracite coal mining is still going strong in eastern Pennsylvania, contributing up to 1% of the state’s gross domestic product. In 1995, over 2,000 workers worked in the anthracite coal mining industry. The majority of the mining at the time involved reclaiming coal from nearby closed mines’ slag heaps (waste dumps from previous coal mining). There is also some underground anthracite coal being mined.

Russia and South Africa are two countries that produce HG and UHG anthracite. In various metallurgical coal applications, HG and UHG anthracite are used as a coke or coal replacement (sintering, PCI, direct BF charge, pelletizing). It’s used to make ferroalloys, silicomanganese, calcium carbide, and silicon carbide, as well as ferroalloys, silicomanganese, calcium carbide, and silicon carbide. Lower-quality, higher-ash anthracite is exported from South Africa to Brazil for use in steel production.

Did You Know?

  • Anthracite coal is sometimes referred to as “hard coal.” Anthracite coal is a highly carbonated fossil fuel that produces the most heat of any fossil fuel on the market, and its low sulphur content makes it a very clean-burning fuel.

  • Bituminous coal is also known as “soft coal,” while anthracite is known as “hard coal.”

  • Nakomati anthracite is a private company located in South Africa. It is one of the famous anthracite mining industries.

  • ZAC (zululand anthracite colliery) is known as the “sole producer of prime anthracite” in South Africa.

[Chemistry Class Notes] on Applications of Colloids Pdf for Exam

All the gems and juices you can see in the image above are colloids. Have you felt water droplets in the fog? Yeah! Fog is also an example of a colloid. In fog, water molecules are dispersed in the gas. In the same way, you must have observed many such examples of colloids in your daily life. 

So, this article will discuss what colloids are, the properties of colloids and applications of colloids.

What are Colloids? 

In chemistry, colloids are heterogeneous mixtures of two substances in which minute particles of one substance are dispersed in another substance. The substance whose minute particles are suspended in another substance is called the dispersed phase, while the substance in which it is suspended is called dispersion medium. For example, in the fog dispersed phase is water (liquid) and dispersion medium is different gasses. We can’t see particles of a dispersed phase in colloids by naked eyes as they are very small in size.

Dispersed Phase

Dispersing Medium

Examples

Liquid

Gas

Fog, Mint

Solid

Gas

Smoke, automobile exhaust

Gas

Liquid

Shaving cream

Liquid

Liquid

Milk

Solid

Liquid

Mud

Gas

Solid

Foam, rubber

Liquid

Solid

Jelly, butter

Gas

Solid

Garnet, citrine

Examples of Colloids 

We see many colloidal solutions around us. Many food items such as cake, milk, bread, butter, ice cream, fruit juices, whipped cream etc. are examples of colloids. Apart from these, fog, mist, clay etc., are also examples of colloids. We are providing a list of examples of colloids with their dispersed phase and dispersing medium below –

Properties of Colloids 

Colloids show the following properties.

  • It is a heterogeneous mixture. 

  • The size of colloidal particles is very small. Their particle size ranges between 1-1000 nanometers. 

  • It shows the Tyndall effect. It means it scatters the beam of light and shows its path through itself. 

  • They don’t settle down when left undisturbed for some time. It means colloidal solutions are quite stable. 

  • They cannot be separated by the filtration process. 

  • They can be separated by centrifugation.

  • Colloidal particles show Brownian movement.

Applications of Colloids 

  • Colloids have various applications in many fields. Some uses of colloids are listed below –

  • Colloids are used in the foods and food industries at a large level. Many foods which we consume are actually colloidal in nature. Such as milk, cheese etc. 

  • Colloids have various applications in the medicinal field as well. Many medicines which we use are in the form of emulsions. Antibiotics such as penicillin and streptomycin are given in the form of colloidal solutions so that they can be absorbed by the human body easily. 

  • Colloids are used in water purification. 

  • Sewage water contains impurities like dirt, stool, urine etc. which are dispersed in water. Thus, it forms a colloidal system. These can be removed by electrophoresis

  • Smoke is also a colloidal system of carbon particles in the air. This can also be purified by electrophoresis. 

  • These are used in artificial rain as well. 

  • Rubber is obtained by a colloidal solution called latex through coagulation. 

  • Treatment of the skin of animals to get leather is called tanning. In the process of tanning, colloids are used. 

  • Micelles formed in the cleansing action of soaps are colloids.

  • Colloids are used in the form of smoke in smoke screens to hide some things in the military. 

  • The blue color of the sky is due to a colloidal property shown by the sky. Dust particles dispersed in the air scatter sunlight. 

  • Many nanomaterials are prepared by colloids. 

  • These are used in metallurgy during froth floatation. 

  • These are used in the treatment of hypovolaemic patients.

  • A silver colloid is used as a germicidal agent. 

  • Many colloids are used as anticancer drugs, such as copper colloids. 

  • Colloids are used in the preparation of anti-syphilis antibodies. 

  • Proteins are colloids and are used in various ways. 

  • These are used for targeted drug delivery. 

  • These are used as cosmetic ingredients for many cosmetic products. 

  • These are used as fungicides and pesticides. 

  • These are used in plastic surgery of many body parts. 

  • These are used in dentistry. 

  • These are used in wound dressing materials as well.

This was brief on colloids with emphasis on their applications; if you want to get detailed study notes on the topic colloids, then register yourself on or download the learning app for Class 6-10 IIT JEE and NEET.

[Chemistry Class Notes] on Asbestos Mineral Pdf for Exam

The asbestos mineral is a naturally occurring silicate mineral that is a type of fibrous silicate. These fibrous minerals are composed of thin fibre crystal. Each fibre is composed of a sub smaller unit known as fibrils. These fibrils can be released into the atmosphere by the erosion process like abrasion. These minerals are also called silica asbestos or asbestos silicate as they are made up of silicate units.

Asbestos Rock

As we know asbestos is a naturally occurring mineral, there are three main types of rock in which asbestos is found naturally. Therefore, these rocks are also called asbestos rock. These three main types of natural asbestos rock are:

1. Serpentine Asbestos Mineral

It is white in colour. The serpentine asbestos mineral is also known as chrysotile.

2. Amphibole 

It includes actinolite asbestos rock, amosite asbestos rock (brown in colour), anthophyllite, crocidolite also known as a blue asbestos rock (blue in colour), and tremolite.

Other than the above-mentioned rocks, some other rocks are also present in the natural environment in which little amount of asbestos is found. These types of rock include metamorphosed dolostones, metamorphosed iron formations, carbonatites, and alkalic intrusions. Faulting and fracturing of these rocks Contribute to the formation of asbestos. These changes in the natural environment take place due to the increased temperatures, pressures, and the presence of water. The number of asbestiform minerals and asbestos in these rocks can range in size from commercial-grade ore bodies to thin impure veinlets or low-grade occurrences.

Asbestos can be released from these rocks to the atmosphere by the erosion process like rocks broken or crushed. Asbestos can also be released from asbestos-containing soils by stirring up. 

Asbestos Mining

In India, there are more than thirty asbestos mining sites or mines that are in operation that produces around 2800 tones of asbestos silicate mineral per month. The main form of asbestos minerals produced from mining include; chrysotile and tremolite. In recent years a major quantity is imported from Canada that is around 70%. The quality of asbestos silicate minerals produced in India is very poor. Mining and milling and other related processes expose people to dreadful diseases like cancer and related diseases.

Asbestos Ore

The important asbestos ore:  

Asbestos Mineral Uses

  • Asbestos is used in making the Chlor alkali diaphragm membrane. 

  • It is used in making protective and decorative coating on the walls.

  • It is used in making fire blankets.

  • It is used in making stage curtains.

  • Asbestos is present in dental cast lining.

  • It is used in floor tiles.

  • It is used in cement building material.

  • It is used for making insulating mattresses and rope.

  • It is used in sprayed fire-proofing products.

  • It is used in making water and sewage pipes.

  • It is used in boilers.

  • It is used as an insulating material.

What are Asbestos-Related Problems?

Naturally occurring asbestos is not a health problem; it will cause problems only when it gets disturbed. Asbestos is composed of long silica fibres that are invisible to the naked eye. If asbestos mineral fibres are present in the air you breathe, you might inhale the asbestos fibres by your nose which can transfer to your lungs. Inhaling the fibres inside the body is the primary way to get exposed to the asbestos mineral. People living in a naturally occurring asbestos mineral area have a slight risk of asbestos-related disease. The chances of developing an asbestos-related disease vary from person to person. It depends upon the immunity of the person, a dose of the consumed asbestos mineral fibres, and the duration of the exposure. The number of fibres that have been breathed in and for how long, and fibre type alters the asbestos-related disease in a different person. 

Some people can also be exposed to higher levels of asbestos at some times in their lives; for example in their workplace, community or home. Workers that work in the mines have also been known to develop asbestos-related diseases. These workers carry asbestos fibres home on their clothing, skin and hair. Asbestos can cause problems like:

  • It can develop pleural plaque.

  • It can cause chronic lung disease.

  • Asbestos can cause lung cancer.

  • It is responsible for causing mesothelioma.  

Did You Know?

  • Asbestos was nicknamed “the magic mineral”.

  • Asbestos occurs in some soils.

  • Asbestos is not considered a toxic mineral until it is left disturbed.

  • NOA is called naturally occurring Asbestos.

[Chemistry Class Notes] on Atomic and Molecular Masses Pdf for Exam

We characterize the matter as anything that has mass and occupies some space. Since matter is characterized as whatever has mass and occupies room, it ought not to be astonishing to discover that atoms and atoms have mass. Singular particles and atoms, be that as it may, are exceptionally little, and the masses of individual particles and atoms are additionally little. For plainly visible items, we use units (for example, grams and kilograms to express their masses). However, these units are excessively huge to serenely portray the masses of individual particles and atoms. Another scale is required. 

Different elements were contrasted and the atomic mass of hydrogen and their overall masses were acquired. The current situation is unique and now the standard utilized for atomic masses is carbon 12, an isotope of carbon. This standardization has been acknowledged everywhere on the globe. The mass of 12C is 12 atomic mass units and all the elements are doled out their particular masses as indicated by this norm. One atomic mass unit is equal to 112th of the mass of a carbon-12 molecule. The word amu that is atomic mass unit has been supplanted by ‘u’ which means bringing together mass. 

If the element contains isotopes, the atomic mass of that element is the sum total of the total elements multiplied by the atomic mass of the individual isotopes. On the off chance that the elements have isotopes, at that point, the atomic mass of the element is the summation of the general plenitude of the element in multiplication with an atomic mass of the separate isotopes. In this article, we will learn about the atomic and molecular masses and the relative molecular mass definition chemistry.

Atomic Mass

The atomic mass of an element is the number of times a molecule of that element is heavier than an atom of carbon taken as 12. One atomic mass unit is equal to one-twelfth of the mass of a particle of carbon 12 isotope. The atomic mass of an element is the normal relative mass of its particles when contrasted with a molecule of carbon 12 taken as 12. 

Fractional bounty of an isotope is the fraction of the absolute number of particles that are included in that specific isotope. The atomic mass of an element = (Fractional plentitude of isotope 1 × mass of isotope 1) + (Fractional plentitude of isotope 2 × mass of isotope 2).

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Gram Atomic Masses 

The atomic masses of elements that are expressed in grams are their gram atomic masses. For eg: the atomic mass of an oxygen molecule is 16 amu. 

Hence, the gram atomic mass of oxygen is 16 g. 

Molecular Mass 

The sub-atomic mass of a substance is the number of times the particle of the substance is heavier than one-twelfth the mass of an atom of carbon – 12. Or on the other hand, the sub-atomic mass is equal to the whole of its atomic masses of the apparent multitude of particles present in one particle of a substance. For eg: water

The atomic mass of H= 1 unit 

The atomic mass of O =16 units 

The sub-atomic mass of water = 2 × atomic mass of H + 1 × atomic mass of O 

= 2 × 1 + 16 × 1 

= 18 units 

Gram Molecular Mass 

The sub-atomic mass of a substance expressed in grams is the gram sub-atomic mass. For eg: Molecular mass of oxygen = 32u 

∴ Gram sub-atomic mass of oxygen = 32 g

[Chemistry Class Notes] on Barium Hydroxide Pdf for Exam

Are you someone looking for all the information about barium hydroxide right from definition to uses? You have reached your destination because here provides all the information on the topic of Barium Hydroxide – Definition, Chemical Structure, Properties and Uses. The topic starts with the definition and moves on to cover everything related to the topic.  

 

Barium Hydroxide is a white granular compound. It is made up of Barium oxide and water. It is mainly used to produce other Barium products. Barium hydroxide has the chemical formula Ba(OH)₂ₓ. One of the principal compounds of the element barium is its monohydrate, which is alternatively known as baryta or baryta-water. However, in the commercial field, the white granular monohydrate of barium is used for many applications. 

 

Chemical Structure of Barium Hydroxide

The chemical formula of Barium Oxide is Ba(OH)₂. The chemical formula of Barium Hydroxide is interesting. As you can see from the name, Barium Hydroxide is made up of Barium and Hydroxide. So, logically speaking, the formula should be Ba(OH). Then why do we write Ba(OH)₂ as the formula of Barium Hydroxide? This is because Barium has two positive ions while hydroxide has one negative one. So in order to show Barium as a neutral compound, we add another hydroxide to Barium Hydroxide and make it neutral

 

 

Properties of Barium Hydroxide

Molar Mass

In order to find the molar mass of Barium Hydroxide, we need to add the molar masses of the elements that build this compound. The molar mass or molecular weight of Barium is 137.33. There is only one Barium in the compound. The molar mass of hydrogen is 1.008. There are two hydrogens in the compound. So the total molar mass of the two hydrogens combined is 2.016. The molar mass of oxygen is 15.999. There are two oxygens and hence the total molar mass of the two oxygens combined is 31.998. Now if we add these numbers we get 171.344. So the molar mass of Barium Hydroxide is 171.344g/mol.

 

Barium Oxide: A Strong Base

A base is a chemical species that reacts with water to give out hydroxide ions. A strong base is that base that can get completely dissociated in H2O to give out the exact number of anions and cations that the elements in the unbroken base had.

 

 

Melting Point

The melting point of Barium Hydroxide differs with the amount of water in it. The octahydrate form of Barium oxide melts at 78-degree celsius. The monohydrate form melts at 300-degree Celsius and the anhydrous form melts at 407-degree celsius.

 

Solubility

Although Barium Hydroxide is soluble in water, it is only slightly soluble. You need a Barium Hydroxide compound with a Molar Concentration of 0.1 M if you want it to dissolve in water.

 

Boiling Point

Barium Hydroxide boils at 780-degree celsius. If you keep on boiling and the temperature reaches 800-degree celsius, it will decompose and give out Barium Oxide.

 

Other Properties of Barium Hydroxide 

  • Barium hydroxide is white in colour.

  • It generally appears as a granular solid.

  • It is odourless.

  • The pH of Barium Hydroxide is 11.27

  • The density of the monohydrate form of Barium Hydroxide is 3.74 g/cubic cm. And the density of the octahydrate form is 2.18 g/cubic cm.

 

Properties of Barium Hydroxide At A Glance

Physical Appearance

White, Odourless and Granular

Chemical formula

Ba(OH)₂

Molar mass

171.344 g/mol

pH of Barium Hydroxide

11.27

Density

3.74 g/cubic cm when it comes to the monohydrate form. 2.18 g/cubic cm when it comes to the octahydrate form.

Solubility

It is slightly soluble in water ( Upto 0.1 M of molar concentration)

Melting point

78 degrees C ( For the octahydrate form), 300-degree C (for the monohydrate form), 407 degrees C ( for the anhydrous form)

Boiling Point of Barium Hydroxide

780 degree C

 

Endothermic Reaction

The article on Barium Hydroxide will remain incomplete if we don’t talk about endothermic reactions and the role of Barium Hydroxide in it. An endothermic reaction is any reaction that borrows heat from the surrounding areas. The area thus becomes noticeably cool.

 

You can see this endothermic reaction if you mix Barium hydroxide with ammonium chloride. As you mix the two compounds in a beaker the temperature shoots down rather too quickly. If you measure the temperature inside the beaker, you will see that it has gone down below -20 degrees. The reaction absorbs the surrounding heat and results in the production of ammonia, barium chloride and water.

 

Uses

Barium hydroxide is primarily used to produce other barium products. However, these products are discussed later on. Barium hydroxide is also used in laboratories to measure the concentration of weak acids. This process is called titration. This compound is also used to make glass, grease or other alkalis. It is also used in the treatment of sewage water. 

 

Here’s a Recap

In case you have forgotten earlier topics, worry not, we have got you covered. We have provided you with a few points to recollect this topic in less than 3 minutes.

  • Barium hydroxide is a white, granular compound.

  • It is made of Barium and Hydroxide ions.

  • In its original form, it is ionic.

  • Barium hydroxide has a molecular weight of 171.344 g/mol.

  • Barium hydroxide is a strong base as it dissociates itself completely in water and gives out BaO cation and Hydroxide cation.

  • It takes 78-degree Celsius for the octahydrate form of barium hydroxide to melt. It takes 300 degrees and 407-degree Celsius for the monohydrate and the anhydrous forms to melt.

  • The boiling point of Barium hydroxide is 780-degree Celsius. If you heat the compound further, it results in thermal decomposition and you will get Bari
    um Oxide.

  • Barium Hydroxide can get dissolved in water, it is only slightly soluble. Barium Hydroxide compound with a Molar Concentration of 0.1 M will dissolve in water. The compound with a higher molar concentration cannot dissolve in water.

 

Barium Hydroxide Can Be Hazardous

Although barium hydroxide is not as dangerous as, say, acids, it is a corrosive material. It can harm your skin, eyes, fingers etc. There is evidence of Kidney damage too because of the prolonged exposure to barium hydroxide. Inhalation of barium oxide can harm the respiratory tract. Hence, in the industrial setting, barium hydroxide is handled carefully by trained workers. 

 

Barium hydroxide is too dear for the teachers to show you how the endothermic reaction moves forward. The compound is not used in the domestic setting. Yet, you must read about the compound because of its unique properties and because of its applications in industrial areas.

Conclusion

Thus we realise how important barium hydroxide is not just from an exam perspective but also the application point of view. This topic will not just help you score good marks in the chemistry exam but also chemistry practicals. We suggest you be very alert during the practicals, this will add more wisdom to your knowledge base.  

has covered this topic in the most holistic way possible for you. To make sure you get enough revision, towards the end you are also given the recap of the context.

 

You can study other topics of Chemistry from the website for free. All the topics are made available to you in web content format, thus your time and device storage will be saved. 

[Chemistry Class Notes] on Benzene – Physical and Chemical Properties Pdf for Exam

The word ‘Benzene’ is derived from the name of Gum Benzoin, which is an Aromatic form of Resin. Michael Faraday first discovered Benzene in some illuminating gas, and it was named so by Mitscherich, a German Chemist. Benzene is an Organic Compound with the Chemical formula of C6H6. It is also widely known as the father of the Aromatic Compounds. Benzene is the simplest HydroCarbon and has a very sweet Aroma.

Benzene Chemical Structure and Detailed Description

C₆H₆ is the Chemical formula of Benzene. It is a form of Cyclic HydroCarbon, i.e., each of its Carbon atoms is arranged in a ring of 6 members, and is only bonded with 1 Hydrogen atom. There are two resonance structures available in Benzene.

It is an Aromatic PetroChemical and crude oil’s natural element. Having an odour just like Gasoline, the Liquid is colourless, Highly Toxic, and Carcinogenic. It naturally occurs in the Environment and forms in volcanic eruptions and forest fires. It is also produced in industries using coal and oil.

Benzene Preparation and Properties

For the preparation of Benzene, the following methods are carried out.

1. Benzene Preparation from Alkynes

With the help of Cyclic polymerization, Benzene can be prepared from Ethyne. In this method, Ethyne passes from a tube of red-hot iron at 873K, the molecules of Ethyne then goes through Cyclic polymerization for the formation of Benzene.

2. Benzene Preparation from Aromatic Acids

Benzene can also be prepared from the Aromatic acids by a Decarboxylation Reaction. In this method, the Sodium Salt of Benzoic Acid heats with Soda Lime for the formation of Benzene and Sodium Carbonate.

3. Benzene Preparation from Phenol

Benzene can be prepared from the Reduction of Phenols. In this method, the vapours of Phenol pass over the heated dust of Zinc. The dust then reduces the vapour for the formation of Benzene.

4. Benzene Preparation from Sulphonic Acids

Benzene can be prepared through the Hydrolysis of Sulphonic Acids. In this method, the acid is exposed to heated steam, and this leads to the formation of Benzene.

[ C_{6} H_{5} + SO_{3}H + H_{2}O rightarrow C_{6}H_{6} + H_{2}SO_{4}]

Benzene is a naturally occurring substance that has the capability of Chemical production. It is also used in the industries for serving various needs. Here, we will describe the properties of Benzene.

Now, let us discuss Benzene physical and Chemical properties.

Physical Properties of Benzene:

  1. Benzene is a colourless Compound, and the physical state of Benzene is liquid.

  2. Benzene melts at 5.5 °C, and it boils at 80.1 °C.

  3. Benzene is not miscible in water and is soluble in organic solvents.

  4. It has an Aromatic odour.

  5. The density of Benzene is 0.87 gm/cm3 and is lighter than water.

  6. Benzene exhibits resonance.

  7. It is inflammable, and its combustion produces sooty flames.

Chemical Properties of Benzene and its Derivatives:

The Chemical composition of Benzene is C6H6 , i.e., it is made of 6 Carbon atoms and 6 Hydrogen atoms.

1. Nitration of Benzene

At 323-333K, Benzene reacts with nitric acid in the presence of sulphuric acid for the formation of nitroBenzene. 

2. Sulfonation of Benzene

It is a process in which Benzene is heated with fuming sulphuric acid, i.e. H2SO4 + SO3 for the formation of Benzene sulphuric acid. It is a reversible reaction.

3. Halogenation of Benzene

In the presence of Lewis acids (FeCl2, FeBr2), Benzene reacts with the halogens for forming the aryl halides.

4. Friedel Craft’s Alkylation Reaction

Benzene gets treated with an alkyl halide in the presence of any Lewis acid for the formation of alkylBenzene.

5. Friedel Craft’s Acylation Reaction

Benzene is treated with an acyl halide in the presence of any Lewis acid for the formation of acyl Benzene.

6. Addition Reaction

Adding chlorine to Benzene in the presence of UV rays leads to the formation of Benzene hexachloride, also known as gammaxene.

7. Combustion of Benzene

During the combustion of Benzene, it burns with a sooty flame and evolves CO2.

[ C_{6}H_{6} + O_{2} rightarrow CO_{2} + H_{2}O]

Benzene Uses

Benzene serves many industrial needs, like the manufacturing of lubricants, rubbers, plastics, dyes, etc. Other than these, Benzene also has some other uses in non-industrial matters. However, the toxic nature of Benzene limits its usage, and there are only a few uses are listed below.

  1. It is used for preparing Phenol. It also helps in the preparation of Aniline, which is used in dyes. Also, it is used in the manufacture of detergents.

  2. Earlier, Benzene also helped in the degreasing activity of metals.

  3. It is used for the manufacture of nylon fibers.

  4. Benzene is used for effective formation of other Chemicals, like cumene, alkylBenzene, ethylBenzene, nitroBenzene, etc.