Chemistry

Properties of Metals

In this post, we will list down a few important properties of metals and discuss them briefly. Important Properties of Metals In general, metals have high densities In general, metals have high melting points and high boiling points In general, metals are good conductors of heat and electricity In general, metals are malleable (can be […]

Allotropes of carbon – Diamond & Graphite

Allotropes are different forms of the same element in the same state. The different forms of solid carbon are called allotropes of carbon. Diamond & Graphite are two crystalline allotropes of carbon. A few other elements also have allotropes. Oxygen has two allotropes – oxygen (O2) and ozone (O3). Diamond and graphite are both made […]

Electrolysis & manufacturing of Sodium & chlorine

Sodium and chlorine are manufactured by the electrolysis of molten sodium chloride. When an electric current passes through molten sodium chloride, a shiny bead of sodium is produced at the cathode, and chlorine gas forms at the anode. This decomposition is caused by electrical energy in the current. In this post, we will be explaining […]

What are the products of electrolysis?

When compounds are electrolysed, new substances are produced at the electrodes. For example, when electricity is passed through molten sodium chloride, pale green chlorine gas comes off at the anode, and shiny molten sodium forms at the cathode. Apparatus that helps to investigate the products at the electrodes when aqueous solutions are electrolysed The apparatus […]

Which substances conduct electricity?

Some substances do not conduct electricity at all; others conduct electricity in some circumstances, but not in others. In this post, we will see which solids conduct electricity. Also, we will see which liquids conduct electricity. Which solids conduct electricity? The only common solids which conduct electricity are metals and graphite.When metals and graphite conduct […]

What is a molecule?

A molecule is the smallest particle that can have a separate, independent existence. When atoms of the same element join together the result is a molecule of an element. When atoms of different elements join together the result is a molecule of a compound. For example, a molecule of water contains two atoms of hydrogen […]

Relative Formula Mass of a compound

Relative atomic masses can be used to compare the masses of different atoms. Relative atomic masses can also be used to compare the masses of molecules in different compounds. The relative mass of a compound is called the Relative Formula Mass (symbol Mr). How to Calculate relative formula masses The relative formula mass of a […]

What is a Symbol equation and how to Balance it?

Reactions such as magnesium burning with oxygen are described with equations. Word equations describe the reactants (the starting substances) and the products (the final substances). Chemical or symbol equations describe what happens to the atoms, and how many of each there are in the reaction. In this post, we will focus on word equations and […]

Solubilities of various salts in water

In this post, the solubilities of various salts in water at 20 °C are listed in a table (figure 1). In this list, you can easily notice the wide range in solubilities, where silver nitrate has a very high solubility of 217 g per 100 g water and silver chloride has a very low solubility […]

Naming convention of salts | The names of salts – rules

The data in the table above shows how the name of a salt comes from its parent base and acid. So, magnesium oxide and nitric acid would produce magnesium nitrate. Acids with names ending in ‘-ic’ form salts with names ending in ‘-ate’. Thus, the salt from sulphuric acid will have ‘sulphate’, salt from nitric […]

What is titration? | How to carry out a titration?

Titration is an important method to determine the concentration of either an acid or alkali. It works by knowing the volume and concentration of one solution needed to neutralize the other. From this, you can calculate the unknown concentration. When an acid is neutralized by a base, the pH of the solution changes. We can […]

How Kinetic theory of matter explains Changes of state?

The kinetic theory of matter can be used to explain how a substance changes from one state to another. A summary of the different changes of state is shown in Figure 1. These changes are usually caused by heating or cooling. Explaining Melting and freezing with the help of the Kinetic theory of matter When […]

The kinetic theory of matter

The idea that all substances contain incredibly small moving particles is called the kinetic theory of matter. The word ‘kinetic’ comes from a Greek word meaning moving. [Related Post: Kinetic Theory of gases] The main points of the kinetic theory of matter The main points of the kinetic theory of matter are: All matter is […]

Some reversible chemical reactions with equations

Reactions that can be reversed are called reversible reactions. Most of the chemical reactions are irreversible. But there are some processes that can be reversed. ice to water, and water to ice For example, ice turns into the water on heating: If the water is now cooled, ice re-forms. These two parts of this reversible […]

Salts – fundamentals

What are salts? Salts are formed when acids react with metals, bases, or carbonates. Most salts contain a positive metal ion and a negative ion composed of one or two non-metals. common properties of Salts Salts have properties in common. Salts are ionic compounds Salts have high melting points and boiling points Salts are electrolytes […]

Bases and alkalis – fundamentals

In this post, we will study the fundamentals of Bases and Alkalis (fundamentals, definition, differences, examples, reactions of alkalis with water, strong and weak alkalis, etc.) Bases Bases are substances that neutralize acids. They are the chemical opposites of acids. The largest group of bases are metal oxides, hydroxides, and carbonates, such as sodium oxide, […]

Structure of Water molecule – revision notes

In a water molecule, an oxygen atom shares a pair of electrons with each of two hydrogen atoms with polar covalent bonds. Oxygen has six outer electrons and needs two more to satisfy the octet rule, achieving the noble gas structure of eight. Each hydrogen atom needs one more electron to fill its outer orbital […]

The Halogen Group – a general idea

The Halogen Group is One of the most reactive groups in the periodic table, this set includes non-metals. The name “halogen” means “salt former”, which refers to the way that elements in this group react with metals to form salts, such as sodium chloride, widely known as common salt. Tennessine (Ts) is an artificial halogen. […]

Internal Energy of a thermodynamic system

In this post, we have defined the Internal Energy of a Thermodynamic System. We have also identified the components of Internal Energy. Definition of Internal Energy in Thermodynamics In thermodynamics, the internal energy of a thermodynamic system, or a body with well-defined boundaries, denoted by U, or sometimes E, is the total of the kinetic […]

List of elements (alphabetically arranged in a pdf)

In this post, we present an embedded PDF file that contains the list of elements with their symbol, atomic number, and molar mass. The elements are arranged alphabetically, starting from Actinium (Ac) and ending with Zirconium (Zr). PDF with list of elements with symbol, atomic number, & molar mass

hybridization model & hybrid orbitals

In this post, we will explain the hybridization model & Hybrid orbitals in an atom. Hybridization model To explain how the orbitals become rearranged when an atom forms covalent bonds, a special model is used. This model is called hybridization. The hybridization model is the mixing of two or more atomic orbitals of similar energies […]

Ionic Compounds & their chemical formula structure

In this post, we will cover the definition & a few examples of Ionic Compounds. We will also see how the chemical formulas of Ionic compounds are constructed. A brief mention of Ionic Bonding is also made in this post. Definition of Ionic Compound An ionic compound is composed of positive and negative ions that […]

Periodic Table (image)

In this post, we present an image (infographics) that contains the periodic table of the elements. This will be a ready reckoner for those who want a quick view of the periodic table.

Neutralization reaction – definition, examples, equations

The reaction of an acid and a base is called a neutralization reaction. Although acids and bases have their own unique chemistries, the acid and base cancel each other’s chemistry to produce a rather innocuous substance – water. In fact, the general reaction between an acid and a base isacid + base → water + […]

Kinetic Molecular Theory of Gases | Kinetic theory of gases

The kinetic molecular theory of gases is a model that helps us understand the physical properties of gases at the molecular level. This kinetic theory of gases describes this state of matter as composed of tiny particles in constant motion with a lot of distance between the particles. The kinetic molecular theory of gases is […]

Define stoichiometry

In this post, we will briefly define stoichiometry. Then we will see how to Relate quantities in a balanced chemical reaction on a molecular basis. Define stoichiometry The relating of one chemical substance to another using a balanced chemical reaction is called stoichiometry. Using stoichiometry is a fundamental skill in chemistry; it greatly broadens our […]

Oxidation-Reduction Reactions

In this post, we will understand what redox reactions are, we will define Oxidation, Reduction, and Redox. Then we will focus on oxidation numbers and the rules for assigning oxidation numbers.

Energy in Chemical Reactions | exothermic & endothermic

Often, energy is released or absorbed during a chemical reaction. The energy for the welding torch is released when hydrogen and oxygen combine to form water (see the equation below). This welding torch burns hydrogen and oxygen to produce temperatures above 3,000°C. It can even be used underwater.2H2 + O2 → 2H2O + energy Again, […]

Polar and Nonpolar Covalent Bonds – concepts

In this post, we will briefly discuss the concepts of Polar and Nonpolar Covalent Bonds. Polar Covalent bond In some covalent bonds, electrons are not shared equally between the two atoms. These are called polar bonds. Figure 1 shows this polar bond for water. Polar Covalent bonds in a water molecule In a water molecule, […]

Alkanes & The first four alkanes – revision notes

Alkanes are a family of saturated hydrocarbons. Saturated molecules are ones that only contain single covalent bonds. The structures of the first four alkanes are shown in table 1. The table includes the displayed formula which shows all the atoms and all the bonds in each molecule. The first four alkanes The first four alkanes […]

Redox (reduction-oxidation) reactions – revision notes

Redox (reduction-oxidation) reactions involve electron transfer and include all chemical reactions in which atoms have changed their oxidation state. Oxidation state is the state of an element or ion in a compound with regard to the electrons gained or lost by the element or ion in the reaction. In many systems, the reactions occur in […]

Molecular formulae and structural formulae of organic compounds

Chemists use a variety of ways to represent organic compounds. It is useful to know all of these so that you can recognize a molecule regardless of how it is represented. In this post, we will discuss the Molecular formulae and structural formulae of organic compounds. Structural formulae A structural formula is a graphic representation […]

How does carbon bond with other atoms?

Carbon has a number of unique properties that influence how it behaves and how it bonds with other atoms: 1 ) Carbon has four valence electrons. Carbon can thus form a maximum of four bonds with other atoms as depicted in Figure 1. 2 ) Carbon can bond strongly with other carbon atoms forming single […]

Activation energy & chemical Reaction – chemistry Study notes

Activation energy is the minimum energy required to start a chemical reaction. The colliding particles must possess at least this amount of energy for a reaction to take place. Most of the reactions are exothermic but only a few are totally spontaneous and begin without help at normal temperatures (e.g. sodium or potassium reacting with […]

What is Covalent Bonding? – study notes

Covalent bonds are formed when atoms, rather than gaining or losing electrons, share them. Covalent bonds differ from ionic bonds in that there is no transfer of electrons involved. Electrical attraction between the nuclei of adjacent atoms and the shared electrons causes the atoms in a molecule to be held together. This force of attraction […]

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