Home of Knowledge -

Define an acid and a base according to Bronsted-Lowry concept and justify with examples that water is an amphoteric compound

Define an acid and a base according to Bronsted-Lowry concept and justify with examples that water is an amphoteric compound. Answer: Bronsted-Lowry Concept : In 1923, the Danish chemist Bronsted and the English chemist Lowry independently presented their theories of acids and bases on the basis of proton-transfer. According to this concept:  An acid is …

Define an acid and a base according to Bronsted-Lowry concept and justify with examples that water is an amphoteric compound Read More »

Arrhenius Concept of Acids and Bases

Arrhenius Concept of Acids and Bases According to Arrhenius concept (1787): Acid is a substance which dissociates in aqueous solution to give hydrogen ions.   For example, substances such as HCl, HNO3 , CH3 COOH, HCN, etc., are acids because they ionize in aqueous solutions to provide H+ ions.

Differences Between Acids and Bases

Differences Between Acids and Bases Acids and bases shows characteristics properties. Some of them are as follows: Examples of acids: HF, HCl, HBr, HI, H2S, HNO3, HNO2, H2SO4, H2 SO3, H3PO4, H3PO3, H2 CO3 Examples of Bases: LiOH, KOH, NaOH, CsOH, RbOH and H2O. Mg(OH)2, Ca(OH)2, Ba(OH)2, Sr(OH)2 Al(OH)3, Sn(OH)2, Pb(OH)2, Fe(OH)2, Fe(OH)3

Difference between Boiling and Evaporation

Difference between Boiling and Evaporation The main differences between boiling and evaporation are as follows.                BOILING          EVAPORATION 1) Boiling occurs at particular temperature. 1) Evaporation occurs at all temperatures. 2) The entire liquid boils. 2) Evaporation takes place from the surface. 3) Boiling an external source of heat 3) Evaporation can occur using internal energy …

Difference between Boiling and Evaporation Read More »

Evaporation

Evaporation The process of changing of a liquid into a gas phase is called evaporation. Explanation:  Evaporation is an endothermic process in which heat is absorbed (energy is consumed) to convert liquid into solid. In the liquid state molecules are in continuous motion. They possess kinetic energy but all the molecules do not have same …

Evaporation Read More »

Charles’ law of gases

Charles’ law of gases Answer: In 1787 a French scientist, mathematician, inventor and balloonist J.Charles (Jacques Alexander Cesar Charles) studies the relationship among volume and temperature at costant pressure.  He described how gases tend to expand when heated. Statement or Definition: According to this law “ the volume of a given mass of a gas is …

Charles’ law of gases Read More »

Boyle’s Law

Boyle’s Law Definition or statement: volume of a given mass of a gas is inversely proportional to its pressure provided the temperature remains constant. OR The product of pressure and volume of a fixed mass of a gas is constant at a constant temperature. Presenter: In 1662 Robert Boyle , a natural philosopher, chemist, physist and …

Boyle’s Law Read More »

Difference between Turtle and Tortoise

Difference between Turtle and Tortoise Did you recognize that tortoises are turtles, but not all turtles are tortoises? Most of the people use the term “turtle” to reference any reptile with a shell on its back, but there’s several differences between these two unique creatures.

NATURE OF BONDING EFFECT PROPERTIES OF COMPOUNDS

NATURE OF BONDING AND PROPERTIES: Properties of the compounds depend upon the nature of bonding present in them. The compounds having very strong bonding are mostly solid, and those having very weak bonding are gases.   Ionic compounds: The compounds which are formed due to ionic bonding are called ionic compounds. Explanation: Ionic compounds are …

NATURE OF BONDING EFFECT PROPERTIES OF COMPOUNDS Read More »

Intermolecular forces

Intermolecular forces: Relatively weak type of attractive forces which are present in between the molecules are called intermolecular forces. Comparison of chemical bond forces and intermolecular forces present in HCl;- The intermolecular forces are very weak as compare to chemical bond. In HCl the bond in between the hydrogen is very stronger as compared to …

Intermolecular forces Read More »

Types of Chemical Bond

Chemical bond: A chemical bond is defined as a force of attraction between atoms that holds them together in a substance (molecule). Types of chemical bond: Depending upon the involvement of valence electrons in bond formation, there are four types of chemical bond. Ionic bond. Covalent bond. Dative bond or coordinate covalent bond. Metallic bond.

WHY DO ATOMS REACT?

WHY DO ATOMS FORM CHEMICAL BONDS? 0R WHY DO ATOMS REACT? Answer: Atoms combine with each other through chemical bond to gain stability. Atoms achieve stability by attaining electronic configuration of noble gases (He, Ne or Ar, etc) i.e. ns2 np6. Having 2 or 8 electrons in the valence shell is sign of stability. Other atoms except noble …

WHY DO ATOMS REACT? Read More »

Bigger size atoms have more shielding effect thus low ionization energy

Justify the statement, bigger size atoms have more shielding effect thus low ionization energy Answer: Bigger size atoms have more shielding and low ionization energy: Shielding effect is the decrease in attractive forces between the nucleus and outer electrons. Shielding effect increase with the increase of size of the atoms. It is because that with …

Bigger size atoms have more shielding effect thus low ionization energy Read More »

Why and how elements are arranged in a Periodic Table?

Why and how elements are arranged in a Periodic Table? Answer: Reason for arrangement of elements in the periodic table   “OR”  Why elements are arranged in the periodic table : There are more than 100 elements discovered and research is in progress to discovered more elements. Properties of each elements are difficult to study. So …

Why and how elements are arranged in a Periodic Table? Read More »

Why in a ‘period’ the size of an atom decreases if one moves from left to right?

Why in a ‘period’ the size of an atom decreases if one moves from left to right? In a period from left to right the size of an atom gradually decreases because of following reasons. (a) Increase in the effective nuclear charge: Due to increase in nuclear charge, the electrons in the shells are attracted …

Why in a ‘period’ the size of an atom decreases if one moves from left to right? Read More »

Periodic Properties – Atomic Radius, Shielding Effect, Ionization Energy, Electron Affinity and Electronegativity

Periodic properties;- periodic properties of elements are those properties of elements that undergoes gradual decrease or increase from left to right in a period or from top to bottom in a group in periodic table. These properties include: atomic size, atomic radius, shielding effect, ionization energy, electron affinity, electronegativity, etc.   Atomic Radius;- The half of the …

Periodic Properties – Atomic Radius, Shielding Effect, Ionization Energy, Electron Affinity and Electronegativity Read More »

Moseley’s Periodic Table

MODEREN PERIODIC TABLE    OR LONG FORM OF PERIODIC TABLE        OR MOSELEY’S PERIODIC TABLE: In 1913 Henry Moseley discovered a new property of elements, the atomic number. He states that atomic number determines the position of elements. He arranged elements based on their increasing atomic number in periodic table.