Tag: Chemistry

Introduction

Atomic orbitals are the three-dimensional spaces that surround the nucleus and are most likely to contain an electron. The atomic orbitals have been combined to create molecular orbitals. They obtain orbitals in quantum theory, some of which are electron shells in the s, p, d, and f configurations. Although orbitals come in a variety of shapes and sizes, their square can be used to estimate their size or even shape. A total of two, six, ten, or fourteen electrons could fit in the s, p, d, and f subshells, respectively. The particular arrangement of electrons within orbitals in such an atom determines the majority of the chemical compositions of that atom. Depending upon the energy over its electrons, every orbital class seems to have a distinct form. The s orbital has a spherical geometry. The p orbital has the form of a dumbbell, as well as 3p orbitals, which vary in their arrangement across a 3-dimensional axis.

Define Atomic Orbitals

Atomic orbitals are numerical values that provide additional details about the waveform of electrons that inevitably surround atom centers. In the fields of quantum systems and atomic theory, specific mathematical expressions are frequently employed to determine the likelihood of detecting an electron at even a specific area surrounding the nucleus of an atom. The term “atomic orbital” may also refer to the region above an atom’s nucleus where there is the greatest chance that a particular electron will become accessible. Several quantum numbers affect each atomic orbital’s characteristics:

Table of All Possible Atomic Orbitals, where the Value of ‘n’ Ranges from 0 to 5

What do you mean by Atomic Orbital Theory?

An atomic orbital is a statistical term that describes the location or even waveform behavior of such an electron in an atom in both atomic theory and quantum field theory. These electrons, each of which has a distinct spin quantum number s, can fit into any one of these orbitals up to a maximum of two. One such formula can be used to determine whether it is possible to find an electron inside the nucleus of any atom at any particular location.

Summary

Atomic orbitals seem to be the regions around the nucleus of an atom where electrons have often been observed at that particular time. This is a mathematical concept that characterizes the wave-like activity with 1-2 electrons in an atom. Electrons inhabit low-energy orbitals (near such nuclei) before electrons approach higher-energy orbitals. When there is an option of equal-energy orbitals, then occupy the orbitals freely as feasible. That filling of orbitals on its own is termed Hund’s law when applicable. Atomic orbitals are typically denoted by a series of digits as well as letters representing unique features of such electrons linked only with orbitals, including 1s, 2p, 3d, as well as 4f. Primary quantum numbers are values that further indicate levels of energy.

Frequently Asked Questions (FAQs)

1. Is it possible to have an orbital without an electron?

Ans. An orbital’s characteristics are more like the electron residing inside it. This is standard procedure, however irrational this could appear, to refer to ‘Empty orbitals.’ The characteristics of unoccupied orbitals are the same as those computed for electrons within them.

2. What is perhaps the greatest number of orbitals possible?

Ans. The values n=3 & l=1 indicate that it has been a 3p-orbital, however, the number \(f(m_{l}=0)\) indicates that it is indeed a \(3p_{z}\) in origin. As a result, the specified quantum number can only identify one orbital, namely 3p_z.

3. How do electrons fill orbitals?

Ans. According to the Aufbau principle, electrons first occupy lower-energy atomic orbitals before moving onto the higher ones. Based on this method, we may forecast the electronic structure of atoms and ions.

Introduction

While the number of protons is merely the atomic number, the atomic mass of an atom is the sum of both its protons and neutrons. The letters A and Z can be used to denote these. Since it offers the key to the element’s existence, the atomic number is the concept that deals with such a periodic table element. It is only after interacting with this particular proton, which is primarily referred to as this hydrogen isotope’s protium, that the atomic and mass numbers are the same. Keep in mind, in particular, that while the atomic number remains constant, the mass number could change due to the presence of multiple isotopes. The elements are arranged in numerical order by atomic number.

Define Atomic Number

The number of protons in the nucleus of an atom is the atomic number. This is denoted by the letter Z. The number of electrons that surround the nuclei is controlled by the number of protons. In a periodic table with ascending atomic numbers, compounds with similar chemical properties typically cluster in the same column. Different elements have distinctive atomic numbers. For example, all C atoms have an atomic number of sixes, whereas all O atoms have an atomic number of eights.

Define Mass Number

Rutherford proved that an atom’s nucleus, which is composed of protons and neutrons, contains perhaps the majority of the atom’s mass. The mass number refers to the total number of protons and neutrons in such an atom. Atomic mass units are used to measure this. To represent it, the letter “A” is frequently used. This has typically been accomplished by simultaneously adding both neutrons and protons.

For instance,\(Cl^{37}_{17} \) appears to have a mass number of 37. Its nucleus contains twenty neutrons and seventeen protons.

What is the difference between Valency, Atomic number and Mass number

Valency	Atomic Number	Mass Number
The greatest amount of electrons that even an atom could lose, gain, as well as share, in addition to getting stable is referred to as valency.	An atomic no. is the no. of protons that exist in such an atom.	The mass no. within an atom is the total of its protons as well as neutrons.
The electronic arrangement of such an atom could be used to evaluate its valency.	The mass number has always been less than the atomic no.	The atomic no. is always greater than that of the mass number.
The no. of atoms does not affect valency.	No. of neutrons in an atom does not impact its atomic no.	The no. of neutrons inside an atom seems to not affect the mass no.
The no. of electrons does have a direct relationship with valency.	The atomic no. of isotopes seems to be the same.	The mass number of isotopes varies.
Elements are classified as monovalence, divalence, and trivalence based on their valency.	Isobars with similar atomic no. cannot exist.	The mass no. of isobars would be the same.

Energy Levels of Atomic Orbital

When an electron reaches a certain energy level, it is more likely to be found in these regions than in other regions. Orbitals are the name for those sections. Orbitals with roughly similar energies have created sub-levels. The maximum capacity for each orbital is two electrons. The energy of such an electron in a specific atom may be determined solely by the primary quantum number. In order of increasing orbital energy are the following orbitals:

\(1s<2s=2p<3s=3p=3d<4s=4p=4d=4f\)

Summary

The mass number of an atom’s nucleus is an integer equal to the sum of the nucleus’ protons and neutrons. The atomic number, in contrast, is simply the number of protons. Even though their mass is so small compared to that of protons and neutrons, electrons are not counted when calculating mass because they have no impact on the value. The number of neutrons may change, even though the number of protons in such an element’s units remains constant. An electron appears to have very little mass. Therefore, an atom’s atomic mass is roughly equivalent to its mass no. The mass number represents the weight of an atom’s nucleus in atomic mass units.

Frequently Asked Questions (FAQs)

1. Is there a relationship between atomic mass and weight?

Ans: No, atomic mass is indeed the weight of an atom, while atomic weight denotes the weighted average of naturally produced elements.

2. Why does an atomic number refer to as a fingerprint?

Ans: The physical or chemical characteristics of an atom have been exclusively governed by the no. of electrons inside its nucleus, but often along with its nuclear charge: the nuclear charge would be an element’s specific “fingerprint,” as well as Z identifies the chemical components individually.

3. Why is it that a mass number is typically a whole number?

Ans: Since it is the total number of the particles, the mass no. is always a whole number. This varies from the atomic mass unit, which is well recognized, as well as written to 6 decimal points.

Introduction

In 1913, Neil Bohr introduced the Atomic Model, which was based on Planck’s quantum theory of radiation. In overcoming the limitations of Rutherford’s atomic model and describing the hydrogen spectral lines. One such model appeared to be very effective in describing the atom’s stability, as well as the line spectra of an H atom. This model hypothesis correctly predicted smaller atoms such as hydrogen, but when larger atoms were observed, poor phantom assertions were made. However, it does not describe the Zeeman effect, atomic spectra, the Stark effect, or Heisenberg’s Uncertainty Principle.

An Overview of the Bohr Atomic Model

According to Bohr’s Atomic Model, an atom is made up of a tiny, positively charged nucleus surrounded by electrons that move in circular orbits all over the nucleus, attracted by electrostatic forces. He was also awarded the Nobel Prize in Physics for his contributions to atomic structure.

The Bohr Atomic Model’s Postulates

1. Orbits are allowable circular trajectories in that electrons travel all over the nucleus.

2. Because each orbit was associated with a specific amount of energy, they were referred to as energy levels and energy states.

3. Shells of energy have been labelled as 1, 2, 3, 4,… or even K, L, M, N…., and so on. The energy level closest to the nucleus is denoted 1 and is known as the K shell.

4. When travelling at a certain energy level, an electron does not lose or gain energy. In such a given energy state, an electron’s energy appears to be fixed as well as stationary. This is referred to as the normal or ground state.

5. When an electron moves from one orbit to the next, it both emits and absorbs energy. When it travels from a higher energy state to a lower energy state, it releases energy, and when it travels from a lower energy state, it consumes energy.

6. Planck’s equation calculates the absorbed and released energy as the difference between the energies of the energy states.

Bohr’s Atomic Model’s Limitations

1. Bohr’s concept did not explain the atomic spectrum of elements with more than one electron.

2. This does not account for the Zeeman effect, which occurs when a magnetic field breaks spectral lines into densely closed lines.

3. It also fails to illustrate the Stark effect, which occurs whenever spectral lines are broken into fine lines by an electric field.

4. According to Bohr, electrons’ circular orbits appear to be flat. However, a new study shows that an electron travels in 3 dimensions across the nucleus. Because light electrons have a dual nature, this would be centred on de Broglie’s idea.

5. Bohr’s atomic model would not adhere to Heisenberg’s uncertainty principle. According to this theory, determining the precise position and momentum of a tiny circulating particle like an electron with extreme certainty appears to be difficult. As a result, electrons follow a well-defined circular path.

6. Bohr’s hypothesis can never explain the shapes or the structure of molecules. This incorrectly considered large-sized atoms while providing sufficient information about smaller atoms.

Summary

Niels Bohr’s atomic theory includes definite-size electrons as well as energies travelling in orbits around a central nucleus, similar to how planets orbit the sun. To summarise Bohr’s atomic model, the energy states of electrons are focused on the size of such orbits. As a result, electrons in tighter orbits would have less energy. Atoms are unstable because electrons move to drive down orbits, resulting in radiation. Because the electron appears to have no lower orbit to which it can jump, an atom within the smallest orbit has now become completely stable. As a result, it was hypothesised that such an electron could move between these orbits by absorbing and losing photons.

Frequently Asked Questions

1. What exactly is the Bohr Atomic Model Theory?

Ans. Bohr was the first to discover not only that electrons revolve around the nucleus in distinct orbits, but also that the total number of electrons in an element’s outermost shell can be used to define its properties.

2. What is preventing atoms from collapsing?

Ans. The electrons of an atom are kept from collapsing within the nucleus by balancing kinetic and potential energy.

3. What is the radius of a Bohr orbit?

Ans. The Bohr radius, denoted by ‘r,’ has been defined as the mean radius of an electron’s orbit around the nucleus of an H atom in its initial state. Its radius has become a standard value, roughly equivalent to \({5.2917710^{ – 11}}m.\).

Introduction

Calcination and roasting are two processes used to convert ores into oxides. Ores are a naturally occurring substance found in the earth’s crust. These ores are rich in minerals and valuable metals. Metals extracted from ore are required by applying lots of heat, either in the presence or absence of oxygen. Processes such as calcination and roasting are used to convert ores to oxides. The following is a step-by-step diagram for converting ores to oxide and extracting pure metals.

To produce oxide, raw ore is required. During this process of conversion, it expels volatile substances and gas. The removal of volatile impurities in solids and gases results in the extraction of metals from ores’ oxides. Furthermore, electrolytic refining purifies metal.

What Exactly is Calcination?

It is the process of converting carbonate ore to oxide below its melting point using heat in the absence of air or with a limited supply of oxygen. It is also referred to as the thermal decomposition process because it decomposes ore or solid substances without changing their chemical properties and only removes volatile and organic impurities. As an example:

\[ZnC{O_3} \to {\rm{ }}ZnO{\rm{ }} + {\rm{ }}C{O_2}\]

How would you define Calcination?

Calcination is a thermal or heat process that occurs when a solid substance, such as carbonate ore, is heated above its melting point in the absence or limited supply of oxygen. Calcination is derived from the Latin word Calcinare, which means ‘to burn lime’. As a result, the most commonly used ore limestone (calcium carbonates) produces quicklime in the absence of air or oxygen at temperatures ranging from 900 to 1050 °C (calcium oxide). The following is my reaction:

\[CaC{O_3} \to {\rm{ }}CaO{\rm{ }} + {\rm{ }}C{O_2}\]

Why Calcination is Necessary

Calcination is a method of purifying ores. Heating ores or solids to temperatures well below their melting points causes the decomposition or removal of volatile impurities, moisture and water, and organic matter. As an example:

1. Carbon dioxide removal from carbonated ores.

2. Hydrated molecules are extracted from bauxite and gypsum. The following is the reaction:

\[A{l_2}S{O_3}.2{H_2}O{\rm{ }} \to {\rm{ }}A{l_2}{O_3} + {\rm{ }}2{H_2}O\]

1. The extraction of volatile liquids from petroleum and coke.

2. In the preparation of zeolites, ammonium ions are removed.

What Exactly is Roasting?

It is a process of converting mainly sulphide ores into their respective metal oxides when subjected to heat in the presence of air or oxygen. It is one of the metallurgical processes.

How would you define Roasting?

The heating process of converting sulphide ores into metal oxides below their melting point in the presence of air or oxygen is known as roasting. The conversion of ore into oxides alters the chemical properties of the solid ores and results in the formation of a new product after impurities are removed. The roasting of zinc sulphide into zinc oxide results in the following reaction:

\[2ZnS{\rm{ }} + {\rm{ }}3{O_2} \to {\rm{ }}2ZnO{\rm{ }} + {\rm{ }}3S{O_2}\]

Why Roasting is Necessary?

Roasting is a process that converts sulphide ores into oxides by heating them to high temperatures in the presence of oxygen. It is used in the metallurgy process to extract metals or their oxides from ores by removing metallic, non-metallic, toxic, and moisture impurities in the form of volatile substances. The following impurities are removed during conversion:

1. Sulphur removal from sulphide ores.

2. Phosphorus and silicon in flux are removed. Flux is used to remove impurities in the form of slag.

What are the Main Differences between Calcination and Roasting

Calcination	Roasting
In the absence or limited supply of oxygen or air, the ore is heated.	Heat is applied to ore in the presence of an excess of oxygen or air.
Carbonate ores are processed using this method.	This method is employed for sulphide ores.
Only decomposition occurs in this process, and oxygen is not involved in the reaction.	Oxygen is reacted with sulphide ores in this process.
Impurities such as organic matter and water are expelled.	Toxic impurities are removed.
Carbon dioxide is produced along with metal oxide.	Metal oxide and sulphur dioxide are both produced.
The process is also carried out in a reverberatory furnace. The furnace’s holes were kept closed.	It is accomplished in a reverberatory furnace. The holes in the furnace were kept open to allow oxygen or air to enter.

Summary

Metals can be extracted using roasting and calcination processes. Metal-containing ores and minerals are not always present in the oxide form; in this case, roasting and calcination processes are used. Both processes convert the ore to its oxide form. This facilitates the extraction process. These only change when exposed to high temperatures. However, roasting occurs in the presence of oxygen, whereas calcination occurs in the absence of oxygen. During thermal decomposition, roasting produces new products, whereas calcination decomposes the solid substance. Both produce metal oxides, which can then be reduced to metals.

Frequently Asked Questions

1. Is there a physical process involved in calcination?

Ans. It is a decomposition process in which solid substances are broken down when high heat is applied. During this process, no new products are formed. As a result, it is only a physical change or process.

2. How do the calcination reactions take place?

Ans. Calcination reactions occur in retorts and furnaces. The ores or solid substances are stirred in this process to produce a uniform product.

3. Why are roasting and calcination done at temperatures below the melting point?

Ans. If ores are heated above their melting point, they will melt and mix with difficult-to-separate carbonate and sulphur impurities.

Introduction

We use a variety of materials for our necessities. Some are naturally occurring, while others are the result of human labour. Natural resources are plentiful as a result of the abundance of numerous resources in nature. Carbonization contributes significantly to global coal production. Coke is the primary by-product of high-temperature carbonization; approximately 4% of the total input coal is converted into tar and crude benzol (light oil), with significant amounts of gas also produced. The following useful products are produced by processing coal without the use of air:

1. Coal and Gas

2. Coke

3. Tar from coal

Coal and Gas

Coal gas is a combustible vapour fuel extracted from coal that is piped to customers. Town gas is a broader term for gaseous fuels produced for commercial sale and community use. In some places, it is also known as manufactured gas, syngas, or producer gas.

Depending on the techniques used to create it, coal gas is a mixture of gases such as, and, as well as volatile hydrocarbons, with minor quantities of non-caloric gases such as and as impurities.

In the nineteenth century, coal gas, which was primarily a by-product of the cooking process, was widely used for lighting, cooking, and heating. The rise in natural gas production coincided with industrialization and urbanisation, and the by-products, coal tars and ammonia, served as key chemical feedstock for the chemical industry.

Coal, oil, and gas production

Coal gas is produced when coal is heated in an enclosed chamber with no air.

When bituminous coal is heated to 400 °C, it relaxes and coalesces, releasing water steam, rich gas, and tar. Crude oil, coal, and gas are examples of fossil fuels. Over centuries, coal oil was produced from the remains of dead trees and other plant debris. Crude oil and natural gas were extracted from dead sea creatures.

Composition of Coal gas

Coal gas is a gaseous mixture of \({H_2}\), CO, and \({H_4}\) that is produced and used as fuel by destructive distillation (burning bituminous coal in an inert atmosphere). Steam is occasionally introduced to combine with the heated coke, increasing gas production. It is primarily composed of \({H_2}\) and \({H_4}\), with trace amounts of other hydrocarbons, carbon monoxide (a lethal gas), carbon dioxide, and nitrogen. It functions as both a fuel and an illuminant.

Uses of Coal

Coal is used for a variety of things, including

1. Electricity generation: Coal is primarily used to generate electricity. When thermal coal is burned, steam is produced, which powers turbines and generators that generate energy.

2. Liquification, as well as Gasification, is the process by which coal is burned and crushed with steam to produce town gas for home heating and lighting. It is liquefied to produce synthetic fuels that are similar to petrol and diesel.

3. Chemical, as well as other industries: Syngas can be used to create chemicals such as methanol and urea. Coal is widely used in the paper, textile, and glass industries. Coal is also used to make carbon fibre and other speciality components such as silicon metals.

Define Coke and State its Properties

Coal is distilled destructively to produce a high-carbon product. Coke is known as a virtually pure form of carbon due to its high carbon concentration. It’s a greyish-black solid that’s hard and porous. It is used as a reducing agent and a fuel in mineral extraction and steel production.

1. It has nearly pure carbon properties.

2. It is hard, porous, and black.

3. When it burns, it produces no smoke.

Uses of Coke

1. In metal extraction, it is used as a reducing agent.

2. Used in the steelmaking process.

3. It can also be used to generate energy.

Define Coal Tar and State its Properties

Coal Tar is a by-product of the coke manufacturing process. It has the same colour as coke, but it is a thick, viscous liquid with a foul odour. It is used to make synthetic colours, pharmaceuticals, fragrances, plastics, paints, and other products. Not only that, but it is also capable of producing naphthalene balls.

Coal tar was discovered in 1665 and used for medicinal purposes in the 1800s. Itchy skin, UV sensitivity, allergic reactions, and skin discolouration are all potential side effects. It’s unclear whether taking it during pregnancy is safe for the baby, and it’s not usually recommended to take it while breastfeeding.

Coal Tar Applications

Coal tar is primarily used to produce coal-tar products, as well as refined chemicals such as coal-tar pitch and creosote. Coal tar treatments have long been used to treat skin conditions such as eczema and dandruff.

Summary

Coal, as a solid carbon-rich material that is black/brown and occurs in stacked sedimentary layers, is one of the most important fossil fuels. In the future, coal liquefaction techniques could provide readily available, non-polluting fuels and chemical raw materials. Analytical criteria play a significant role in the four coal refining processes described above. Fumes, oils, and tars, as well as soluble but low-volatile extracts, pitches, and cokes, must all be investigated.

Frequently Asked Questions

1. Why do fossil fuels pollute the atmosphere?

Ans. The combustion of fossil fuels produces significant amounts of air pollution and pollutants such as \({H_2}\), CO, and \(S{O_2}\), all of which can contribute to climate change by increasing the greenhouse effect.

2. What exactly is petroleum?

Ans. Petrol, plastic, and other chemical compounds are derived from petroleum, a mineral oil found beneath the ground or in the sea. Petroleum by-products include wax, kerosene, LPG, petrol, lubricating oil, and diesel.

3. What are the different types of coal?

Ans. The least valuable and softest type of coal, with the lowest carbon concentration, is peat. Because of its high moisture content, it is unsuitable for use as fuel.

Anthracite coal is the best available. This type of coal is also known as hard coal. It contains the most carbon. It only produces a small amount of smoke.

Lignite is slightly firmer than peat, but it is still quite soft. It contains more carbon than peat.

Introduction

The distance between the nucleus’s core and the valence shell/outermost shell, known as the atomic radius of an element, serves as a benchmark for the size of its atom. The periodic table shows that the atomic size increases as you move down it and decreases as you move from left to right. The reason for this is that as you move down the group, the number of shells increases, the screening effect multiplies, and the force of attraction weakens, causing the atomic radius to increase. Additionally, the nucleus’ protons increase as you move from left to right, drawing electrons in and shrinking the atomic radius in the process.

Basic understanding of Atomic Radius

The atomic radius is typically defined as the total distance from an atom’s nucleus to its outermost electron orbital. It can be expressed more simply as something resembling a circle’s radius, with the nucleus serving as the circle’s centre and the electron’s furthest orbital serving as the circle’s edge.

What Are the Trends in Atomic Radius? Why Do They Occur?

There are two main trends in atomic radius. One atomic radius trend appears as you move across the periodic table from left to right (doing so within a period), and the other trend appears as you move from the periodic table’s top-down (moving within a group). To help you comprehend and visualise each atomic radius trend, the periodic table below includes arrows that show how atomic radii change.

1. Atomic Radius Trend 1: Atomic Radii Decrease From Left to Right Across a Period

The first atomic radius periodic trend is that as you move from left to right across a period, atomic size decreases. Each additional electron is added to the same shell within a group of elements. A new proton is also added to the nucleus when an electron is added, increasing the nuclear attraction and boosting the positive charge of the nucleus.

In other words, as protons are added, the nucleus gains a stronger positive charge, which in turn attracts the electrons more strongly and draws them in toward the nucleus of the atom. The radius of the atom decreases as the electrons are drawn inward toward the nucleus.

2. Atomic Radius Trend 2: Atomic Radii Increase as You Move Down a Group

Atomic radii rise as you descend in a group in the periodic table, which is the second atomic radius periodic trend. The atom gains an additional electron shell for every group down. The atomic radius grows as each new shell is positioned farther from the atom’s nucleus.

Contrary to popular belief, electron shielding keeps the valence electrons from the nucleus (those in the outermost shell). The electron shielding effect, which occurs when an atom has more than one electron shell, reduces the attraction of the outer electrons to the atom’s nucleus. As a result, electron shielding prevents the valence electrons from getting very close to the atom’s centre, increasing the atom’s radius.

Summary

Atomic radius is characterised by two major trends. The first periodic trend in atomic radii is the increase in atomic radius with decreasing group size. Electron shielding is the cause of this. When a new shell is added, the atomic radius grows as a result of the new electrons’ increased distance from the atom’s nucleus. More protons give an atom a stronger positive charge, which attracts electrons more strongly and pulls them toward the nucleus, shrinking the size of the atom. According to the second atomic radius periodic trend, atomic size decreases from left to right across the period.

Frequently Asked Questions

1. The atomic radius of which of the atoms-Arsenic or Selenium, is the largest?

Ans. Arsenic has a larger atomic radius than Selenium. The reason for this is that the extra protons increase the positive charge in the nucleus, which pulls the electrons closer together, reducing the radius. Arsenic along with Selenium is on the bottom row of the possibilities, but Arsenic is to the left. As a result, its atomic radius is the greatest.

2. What is the atomic radius of F and Ne in Angstrom?

Ans. The atomic radius of F and Ne in Angstrom is 0.72, 1.60. Noble gas elements quoted radii are “van der Waals radii,” which are 40 percent larger than their true atomic radii. As a result, the atomic radius of neon must be substantially larger than that of F. 

3. Is it the size of Ne or \({\bf{N}}{{\bf{a}}^ + }\) that is smaller? Why?

Ans. \(N{a^ + }\) = proton number = 10

Ne = proton number = 10

Both are isoelectronic species, meaning they have the same number of electrons and shells (10 electrons). The size will be determined by the number of protons and nuclear charge. Because the sodium ion has 11 protons, the higher the nuclear charge, the stronger the nucleus’ affinity to valence shell electrons, and the size shrinks. The size of \(N{a^ + }\) is smaller than that of Ne.

Introduction

The different forms of \({H_2}O\) in three different phases are ice (solid), water (liquid), and gas (vapour). The intermolecular spaces in solid particles are very low, they are tightly bound to each other. The intermolecular spaces are comparatively higher in liquids and become maximum in vapours. With the increase in temperature, the kinetic energy of the molecule increases, and the intermolecular interaction between the particles decreases. That is why, on the application of heat, ice is transformed into water and then to vapour Melting and boiling depend on the pressure of the environment. On this basis, a pressure cooker is used to make food in daily life.

What is the melting point of ice?

The melting point of a substance is the temperature at which a solid and liquid phase may coexist in equilibrium, and the temperature at which matter changes from solid to liquid form. The term applies to pure liquids and solutions. The melting point depends on pressure, so it should be specified. This melting point of ice is 0℃. If the temperature increases beyond the melting point, it doesn’t increase the temperature of the matter. Rather, it helps to transform the ice completely into the water. This is known as the ‘latent heat of fusion’ of ice.

What is the boiling point of water? 

With the addition of further heat, the water (liquid) reaches its vapour phase (gaseous state) at a particular temperature. This is the boiling point of water. The boiling point of water is 100℃. The heat that helps to convert the whole water into the gaseous state is known as the ‘latent heat of vaporisation’ of water. 

Online Science Course for Classes 6th, 7th, and 8th. Clear your doubts from the Science experts teacher.

Method to determine the melting point of ice:

The melting point of ice is 0℃. It is determined in a laboratory in the following steps-

• Some ice cubes are taken in a beaker and a thermometer is dipped in it. 
• Heat is applied gently by the Bunsen burner below the beaker.
• The changes in the state of the ice are monitored every minute and the temperature is recorded at which the whole ice is transformed into water. 
• The temperature at which the ice starts melting is noted as \({t_1}\) and the temperature when all the ice melts is noted as \({t_2}\).
• Then the average of \({t_1}\) and \({t_2}\) is calculated. This mean temperature is known as the melting point of ice. 

In this way, the melting point of ice is determined.

Method to determine the boiling point of water:

The water boils at 100℃. It is measured in the laboratory in the following steps-

• A suitable amount of water is taken in a round bottom flask and its mouth is sealed properly with a rubber cork. 
• A thermometer is inserted through a hole in the cork into the r.b flask without touching the water surface. 
• The r.b flask is then heated by a Bunsen burner, and placed on the bottom of a wire gauge supported by a tripod stand. 
• A thermometer reading is taken at a certain interval and the temperatures are recorded. 
• A thermometer reading is taken continuously throughout the boiling of water. 

In such a way, the boiling point of water is measured. 

Factors influencing the melting point and boiling point: 

Factors	Melting point	Boiling point
Pressure	With an increase in pressure, the melting point decreases.	With an increase in pressure, the boiling point increases.
Impurities	Impurities like soluble salts decrease the melting point.	The presence of impurities increases the boiling point.
Size of substance	With an increase in the size of the substance, the melting point increases.	With an increase in the size of thesubstance, van der Waals interaction increases henceboiling point increases.
Intermolecular forces	The melting point increases with an increase in intermolecular interactions, as more energy is needed for bond cleavage.	The stronger the intermolecular forces, the lower the vapour pressure. As a result, the boiling point increases.

Summary: 

The temperature at which ice starts to melt into water is called the melting point of ice (0℃). And the temperature at which water starts to form vapour is termed the boiling point of water (100℃). Intermolecular interaction decreases while moving from ice to water to gas. So, through the melting point of a solid and the boiling point of the liquid, one can have an idea about the extent of interaction among the particles. Moreover, the presence of impurities can be determined from the melting and boiling point values. 

Frequently Asked Questions 

1. Can the size of a molecule affect the melting point value?

Ans: With an increase in size, the van der Waals forces among the molecules increases. As the melting point highly depends on attractive forces i.e. van der Waals interaction, the size can impact the melting point value of the molecule. 

2. Why is the boiling point of water always considered to be 100℃?

Ans: The liquid will start to boil once the vapour pressure of the liquid matches the atmospheric pressure in the region. The point at which water boils is highly influenced by the vapour pressure. At 100℃, the vapour pressure around sea level equals the surrounding air pressure. So, it is considered the boiling point of water. 

3. How can one identify a substance by its melting point?

Ans: Various organic, as well as inorganic compounds, can be identified from their melting point. Also, the extent of purity can be known from their melting point values. If the substance is pure, it will show a sharp melting point instead of a range of melting points in case of an impure substance. 

Introduction

A “mixture” is a combination of two or more substances, such as water and sand, salt and water, or a solution of two solutes, for example. These mixtures are not chemically linked. Hand-picking, winnowing, filtration, distillation, and other techniques are used to separate them. The mixture can be solid in solid, liquid in liquid, gas in gas, and so on. Seawater is also a salt-water mixture. The “evaporation method” is used to separate salt from seawater. Different techniques are used to separate different types of mixtures.

Methods of Separating Mixtures:

Depending on the type of mixture, there are various methods for separating it. In 1840, some prospectors used water to separate gold from a mud mixture; the mud containing gold was filled with water in a pan.

After a while, the pan was twisted to remove the dissolved material, and gold settled in the pan due to its weight. Panning is the process of separating gold from water.

Substances in our environment exist as mixtures, of which there are two types: “homogenous” and “heterogeneous” mixtures.

Different techniques are used to separate them.

Hand-picking: 

The hand-picking method is used to separate the mixtures that are less in quantity and the size of the particle is big. It is usually used to separate stones from grains, rice pulses, etc at home and groceries shops. In this type both the components are in solid form, these are big enough to separate them by hand.

Threshing:

This method is widely used to separate grains from twigs. Farmers use this method to separate hard wheat, rice, pulses, and other grains from their stalks. When food grains reach maturity, the farmer harvests and dry them in the field.

Winnowing:

This method is used to separate the husk from grain or pulses with the help of “ wind” that’s why it is named “winnowing”. 

• In this method, the grains separated by the threshing method contains small twigs, and a husk that is quite thin and light in weight. 
• The grains containing husk are taken in a winnowing basket. The farmer stands at a particular height, taking that basket in the direction of the wind. 
• The farmer falls the grains, the husk, and the twigs get separated by the flow of wind and the grains get cleaned.

Evaporation

1. To separate the mixture into liquid form, “the evaporation technique” is used. The volatile material evaporates, leaving behind a non-volatile solid in the container.
2. The mixture is heated in this method until the liquid portion of the mixture evaporates.
3. The mixture’s solid component is left in the container.
4. This method separates salt from seawater.

Distillation

The “distillation method” is used to separate two or more mixed liquids.

1. A “distillation apparatus” in this method is a plant that contains a flask, a thermometer, a condenser, and a collecting flask (distillate).
2. The mixture is heated to a specific temperature in the distillation flask.
3. The liquid begins to boil and turns into vapour.
4. This vapour is collected in a “distillate” after being condensed in a condenser.

Filtration 

It is a common technique for separating liquids from insoluble solids.

1. The “filter paper” is used in the filtration process to separate liquid from the mixture that is large enough to become trapped in the porous material.
2. To separate water from a sand and water mixture.
3. Heavy impurities are settled down during the sedimentation process.
4. The first liquid, which is above, is then slowly separated from the flask.
5. This method is used to separate mud and water mixtures.

Summary

The elements in the environment are found in combination with other elements. These are both homogenous and heterogeneous mixtures. The mixture can exist as a liquid, solid, or gas. The two materials are not chemically bonded. Depending on the type of mixture, different methods are used to separate it.

Frequently Asked Questions

1. How are the essential oils extracted from the flowers?

Ans. Steam distillation is used to separate the essential oils. The liquid is converted into steam in this process, and the steam vaporises the material with it before being condensed and separated in a retort.

2. Which mixture is separated using cryogenic distillation?

Ans. This method is used to separate the acid gas mixture from the gaseous mixture, LPG, and is similar to removing CO2 from LPG.

3. How are fatty acids, resins, and wax separated from the mixture?

Ans. Drugs, esters, fatty acids, tocopherols, resins, and wax are separated from mixtures using short-path distillation.

Introduction

Mixing various compounds is a key aspect of Chemistry. In science, a mixture is a substance mixed with 2 or more relatively simple materials. These substances can be either elements or compounds. Compounds are unadulterated substances. They are composed of the same molecules. A compound’s molecules are made up of two or more different types of atoms that are chemically bonded together. Mixtures are composed of two or more substances — elements or compounds — that are physically but not chemically combined; they lack atomic bonds. Pure substances are elements and compounds that contain only one type of molecule. A mixture is made up of two or more different types of pure substances. In a mixture, the molecules of these substances do not form any chemical bonds. A mixture’s components retain their chemical independence while physically blending together. These components are frequently visible and distinguishable visually.

What is a Mixture?

A mixture would be a substance made up of 2 or even more components that have been physically mixed to maintain the characteristics of those constituents. In plenty of other terms, the properties of a mixture have been fully determined by the components that are present. We may divide the mixture into groups based on particle size as well as uniformity.

Types of Mixtures

Mixtures can often be divided into two types:

1. Homogeneous Mixtures
2. Heterogeneous Mixtures

Homogeneous Mixtures

Homogeneous mixtures are those that have the same composition but also characteristics across their mass as well as body. Light does not flow via these elements. Sugar syrup, alcohol, as well as water are all homogeneous mixtures with particles of varying sizes that make identification difficult.

Heterogeneous Mixture

Heterogeneous mixtures include those mixtures that do not dissolve properly but also do not have similar content. Particular elements are frequently detectable and might even be isolated using both chemicals and physical properties due to such characteristics. Suspensions, as well as colloids, are often the 2 types of heterogeneous mixtures. For example, water and sand, blood, or starch.

What are Compounds

Compounds are atomic components as well as other elements that are linked collectively with a chemical bond. Depending on the substance, such a bond might be ionic, covalent, as well as metallic. Because all compounds possess a fixed ratio of components, they are uniform. Certain substances differ from elements that normally mix to form only one compound unit in terms of their characteristics. Furthermore, a chemically bonded molecule cannot ever be physically detached.

Types of Compounds

Compounds are classified into 3 types:

• Ionic compounds: They are made up of two oppositely charged ions. Electrostatic attraction holds the ions connected. Water is usually reactive in ionic compounds.
• Covalent compounds: They’re made up of atoms that exchange electrons and are also non-polar, which means they don’t even react with water.

Examples of Compounds

• Water: This is composed of 2 elements: 2 hydrogens as well as 1 oxygen.
• Methane: It is composed of 2 elements: carbon as well as hydrogen.
• Table salt: Sodium, as well as chlorine, are indeed the 2 elements found in table salt.
• Glucose: It is composed of 3 elements: carbon, hydrogen, as well as oxygen.

What are the differences between Mixtures and Compounds?

Compounds	Mixtures
Chemical interaction between two or more components tends to produce compounds.	Mixtures are introduced by directly integrating two or more elements in such a way that no chemical reaction occurs between both components.
To yield a compound, elements must always join in a defined mass proportion.	The proportion of elements is not set or could change.
Throughout the development of a compound, its energy changes.	There is no change in energy.
It cannot be removed physically and must be separated using sophisticated scientific methods.	Physical separation of mixtures is possible.
The constituents’ properties are lost, or the compound generated has distinct physical as well as chemical properties.	A mixture’s constituents maintain its original properties.
Organic as well as inorganic compounds, both are possible.	Homogenous as well as heterogeneous mixtures can exist.
In compound initiation, new bonds have been generated.	There is no new bond forming.
The melting or boiling points of compounds are fixed.	The melting or boiling points of mixtures are not set.

A mixture is formed by mechanically combining two or more components while retaining their distinct characteristics. It can exist as solutions, suspensions, or colloidal particles. Chemical components and compounds, for example, can be mechanically blended or mixed to form mixtures, but no chemical binding or another type of chemical transformation occurs, so each constituent retains its distinct chemical properties.

Frequently Asked Questions

1. What are the basic types of the mixture?

Ans. Two broad categories of mixtures are- 

• Homogeneous mixtures
• Heterogeneous mixtures

2. Bronze is an alloy or mixture of which metals?

Ans. Bronze is a solid-solid mixture of copper(Cu) and Tin(Sn).

3. The solution is which type of mixture?

Ans. The solution is a homogeneous type of mixture where all the components or substances are uniformly distributed that cannot be separated manually or physically.

Introduction

The colloidal solution is one of the significant components of a mixture, along with the two adjacent combinations: true solutions and suspension solutions. In different physical and chemical procedures, all three solutions have variable characteristics and properties, and the significant difference lies in the particle size, appearance, and separation procedure. The three solutions have distinct reactions to the various chemical processes. The dissolving properties of the mixtures differ between the three mixtures due to the variable nature of the solute and solvents involved.

What is a True Solution?

A true solution is a homogeneous combination of two or more substances. In this case, the particle size of the dissolved material in the solvent is less than 10-9 m or 1 nm. Homogeneous means that the mixture’s components form a single phase. The filtration process will not be able to separate the solute from the solution in the solution.

The solute particles do not settle out. The light will never scatter in a true solution. Another distinguishing feature of a genuine solution is its clarity and transparency. A sugar solution in water is an example of a true solution.

What is a Suspension solution?

A suspension solution is a mixture of two or more substances in which the solute particles do not dissolve and remain suspended throughout the solution. Solids are dispersed in liquids in suspension solutions. The particles of the solute are easily visible to the naked eye.

Because the particles are large, they scatter light rays. The path of the ray through the solution is easily visible. Using the filtration method, the particles in the suspension solution can be easily separated. A mixture of chalk and water is a common example of a suspension solution.

An aerosol is a liquid droplet suspension in a gas. Suspensions are further classified based on two factors: a dispersed phase and the dispersion medium.

Want to get an “A” on your Science exams? Let our expert teachers be your guide toward improving your grades and reaching your highest potential. Study Science Subject for classes 6th, 7th, and 8th.

What is a Colloidal Solution?

A colloidal solution is a fluid-suspended mixture of particles of various substances. The particles are microscopically dispersed and soluble/insoluble in this case. Suspension and colloidal solutions are tiny materials that are uniformly distributed. Some of the colloids are translucent due to the Tyndall effect. Some colloids, on the other hand, can be opaque.

You may have heard the term ‘Hydrocolloids’ in the colloids section. This term refers to chemicals that are colloidally dispersed in water. As a result, the solution becomes soluble, altering the rheology of water. 

Colloidal systems can exist in three different states: gas, liquid, and solid. Whipped cream and perfume are two examples of colloidal solutions.

Differences between True Solutions, Colloids, and Suspensions

Attributes	True Solutions	Colloids	Suspensions
Meaning	A true solution is a mixture of two or more substances that is homogeneous.	A colloidal solution is a heterogeneous mixture of particles of different substances suspended in fluid that are microscopically dispersed and soluble/insoluble.	A suspension solution is a mixture of two or more substances in which the solute particles do not dissolve and remain suspended throughout the solution.
Size	The particles in the true solution are tiny (less than 1 nm)	The particles in the colloidal solution are neither small nor large (1-100 nm).	The particles in the suspension solution are large (more than 100 nm)
Visibility to the Naked Eye	The particles are invisible to the naked eye.	The particles are visible to the naked eye.	The particles are visible to the naked eye.
Scattering of Light	True solution particles do not scatter light.	The colloidal solution’s particles are large enough to scatter a light beam.	The suspension solution’s particles are large enough to scatter a light beam.
Example	Sugar Solution	Blood	Sand in Water

Summary

So, as you can see, even though these three solutions appear to be the same, they are not. Each of the three solutions has its own set of characteristics. We hope this article answered all of your questions and helped you understand the differences between true solution, colloidal solution, and suspension.

Frequently Asked Questions (FAQs)

1. What is Ultracentrifugation?

Ans. It is the process of using centrifugal force to separate colloidal particles from contaminants. The impure sol is collected in a tube, which is then placed in an ultracentrifuge.

2. Why are the colligative properties of colloids of low order?

Ans. Because colloidal particles are larger aggregates, the particles in colloids are smaller than in a true solution. As a result, when compared to true solution values at similar proportions, measurements of colligative qualities are of low order.

3. Which effect confirms the heterogeneous nature of the colloidal solution?

Ans. The Tyndall effect confirms the colloidal solution’s heterogeneous character. As light travels through a sol, it is scattered by particles, revealing its route and called as Tyndall effect.