Basic Chemistry: Mole, Lon's and Salts, Acidity and Basicity and Arrhenius Theory

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Table of Contents

  • Introduction

  • Atoms and Elements

  • Atomic number and atomic mass

  • Periodic Table and Chemical Bonds

  • Isotopes

  • Radioisotopes

  • Periodic Table and Chemical Bonds

  • Electronegativity

  • Chemical Bond

  • Compound, substance, Molecule

  • Acidity and Basicity

  • Redox Reaction

Learning Outcomes

After studying this lesson, you shall be able to:

  • mole

  • Ions and salts

  • Arrhenius theory

Mole (Unit)

  • Mole is a chemical mass unit, defined to be 6.022 x 1023 molecules, atoms, or some other unit.

  • The mass of a mole is the gram formula mass of a substance.

  • The number of entities per mole is known as the Avogadro constant, and is determined empirically.

  • The currently accepted value is

  • 6.02214179(30)×1023 mol-1

  • The amount of substance of a solute per volume of solution is known as molarity used to express the concentration of a solution in the chemical laboratory.

  • The most commonly used units for molarity are mol/L (the official SI units are mol/m3).

Ions and Salts

  • An ion is a charged species, an atom or a molecule, that has lost or gained one or more electrons. Positively charged cations (e.g. sodium cation Na+) and

  • negatively charged anions (e.g. chloride Cl-) can form a crystalline lattice of neutral salts (e.g. sodium chloride NaCl).

  • Examples of polyatomic ions that do not split up during acid-base reactions are hydroxide (OH-) and phosphate (PO43-).

  • Ions in the gaseous phase are often known as plasma.

gaseous phase

Gaseous Phase

Acidity and Basicity

Acid-Base Reaction

  • A substance can often be classified as an acid or a base.

  • There are several different theories which explain acid-base behaviour.

  • The simplest is Arrhenius theory, which states that an acid is a substance that produces hydronium ions when it is dissolved in water, and a base is one that produces hydroxide ions when dissolved in water.

Acidity and basicity

Acidity and Basicity

Arrhenius Theory

According to Bronsted-Lowry acid-base theory, acids are substances that donate a positive hydrogen ion to another substance in a chemical reaction; by extension, a base is the substance which receives that hydrogen ion.

Arrhenius Theory

Arrhenius Theory

MCQs

1. What is SI unit of Molarity:

  1. Mol/m-1

  2. mol/m3

  3. Mol

  4. None of the above

Answer: mol/m3

2. Which among the following can act as both acid and base:

  1. 𝐒𝐎𝟐

  2. 𝐇𝟐𝐒𝐎𝟒

  3. SO42-

  4. 𝐇𝟐𝐎

Answer: 𝐇𝟐𝐎

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#Ions and salts

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