– In this subject, we will discuss the Photoelectric Effect and Compton Effect Photoelectric Effect – When a beam of light of sufficiently high frequency is allowed to strike a metal surface in a vacuum, electrons are ejected from the metal surface. – This phenomenon is known as the Photoelectric …
Read More »Atomic Spectrum of Hydrogen
– In this subject, we will discuss the atomic Spectrum of Hydrogen Atomic Spectrum – When an element in the vapour or the gaseous state is heated in a flame or a discharge tube, the atoms are excited (energised) and emit light radiations of a characteristic colour. – The colour …
Read More »Atomic Number and Mass Number
– In this subject, we will discuss the Atomic Number and Mass Number Mosley’s Determination of Atomic Number – The discovery that an atom has a nucleus that carries a positive charge raised the question: What is the magnitude of the positive charge? – This question was answered by Henry …
Read More »Rutherford’s Atomic Model (Experiment, Postulates, weakness)
– In this subject, we will discuss the Rutherford’s Atomic Model (Experiment, Postulates, weakness) Alpha particles – Alpha particles are shot out from radioactive elements with very high speed. – For example, they come from radium atoms at a speed of 1.5 × 107m/sec. – Rutherford identified them to be …
Read More »Subatomic Particles: Electrons, Protons, and Neutrons
– In this subject, we will discuss the Subatomic Particles: Electrons, Protons, and Neutrons Subatomic Particles – We have hitherto studied the properties of the three principal fundamental particles of the atom, namely the electron, proton, and neutron. – These are summarised in this Table: – Nearly all of …
Read More »Electron: Discovery, Charge, Mass, Definition
Cathode Rays – The discovery of electron – The knowledge about the electron was derived as a result of the study of the electric discharge in the discharge tube (J.J. Thomson, 1896). (1) The discharge tube consists of a glass tube with metal electrodes fused in the walls. (2) Through …
Read More »Cyclohexane: Axial and Equatorial Bonds in Cyclohexane
– In this subject, we will discuss the Substituted Cyclohexane: Axial and Equatorial Hydrogen Groups Substituted Cyclohexane: Axial and Equatorial Hydrogen Groups – The six-membered ring is the most common ring found among nature’s organic molecules. – For this reason, we shall give it special attention. – We have already …
Read More »Conformations of Cyclohexane: The Chair and the Boat
– In this subject, we will discuss Conformations of Cyclohexane: The Chair and the Boat Conformations of Cyclohexane: The Chair and the Boat Cyclohexane is more stable than the other cycloalkanes we have discussed, and it has several conformations that are important for us to consider. (1) The most stable conformation …
Read More »Acidity of Carboxylic Acids and Alcohols
– In this subject, we will discuss the Acidity Differences between Alcohols and Carboxylic Acids Acidity of Carboxylic Acids and Alcohols – Carboxylic acids are weak acids, typically having pKa values in the range of 3–5. – Alcohols, by comparison, have pKa values in the range of 15–18 and essentially do …
Read More »The Kinetic Molecular Theory of Gases
– In this subject, we will discuss the Kinetic Molecular Theory of Gases. Introduction to The Kinetic Molecular Theory – The gas laws help us to predict the behavior of gases, but they do not explain what happens at the molecular level to cause the changes we observe in the …
Read More »Acid and Base Dissociation Constants (Ka and Kb)
– In this subject, we will discuss the Acid and Base Dissociation Constants (Ka and Kb) Acid and Base Dissociation Constants – When a weak acid or a weak base is dissolved in water, partial dissociation occurs. – Thus, for nitrous acid, we can write: – where Ka is the …
Read More »Solved problems: Dalton’s Law of Partial Pressures
– Before you solve these problems, you can read this subject for Dalton’s Law of Partial Pressures (Statement, Mathematical, Importance, Application). – Let us understand Dalton’s law by solving these problems. Solved Problems on Dalton’s Law Problem (1) on Dalton’s Law A mixture of oxygen and neon contains oxygen at …
Read More »Dalton’s Law of Partial Pressures (Statement, Applications)
– In this subject, we will discuss Dalton’s Law of Partial Pressures (Statement, Mathematical, Importance, Application). Dalton’s Law of Partial Pressures – Thus far we have concentrated on the behavior of pure gaseous substances, but experimental studies very often involve mixtures of gases. – For example, for a study of air …
Read More »Hybridization and Shapes of Molecules
Hybridization and Shapes of Molecules – In the previous subject, we talked about the concept of Hybridization and the types of Hybridization, but in this subject, we will talk about Hybridization and Shapes of Molecules. – Diatomic molecules must all be invariably linear but tri-and tetra-atomic molecules have several possible …
Read More »Density of gas: Definition, Equation, Solved Examples
– In this subject, we will discuss the Density of gas (Definition, Equation, Solved Examples) The Density of gas – From the ideal gas equation: – If we rearrange the ideal gas equation, we can calculate the density of a gas: – The number of moles of the gas, n, …
Read More »Molar Mass of gas: Definition, Equation, Solved Examples
– In this subject, we will discuss the Molar Mass of gas (Definition, Equation, Solved Examples) The Molar Mass of a gas – From what we have seen so far, you may have the impression that the molar mass of a substance is found by examining its formula and summing …
Read More »Hybridization: Definition, Types, Rules, Examples
– In this subject, we will discuss the Hybridization: Definition, Types, Rules, and Examples – While the formation of simple molecules could be explained adequately by the overlap of atomic orbitals, the formation of molecules of Be, B, and C present problems of greater magnitude having no solution with the …
Read More »Acidity: The relationship between Structure and Acidity
– In this subject, we will discuss the Relationships between Structure and Acidity. – The strength of a Brønsted–Lowry acid depends on the extent to which a proton can be separated from it and transferred to a base. – Removing the proton involves breaking a bond to the proton, and …
Read More »Thermodynamics of Organic Compounds
– In this subject, we will discuss the Thermodynamics of Organic Compounds Thermodynamics of Organic Compounds – For a reaction to be practical, the equilibrium must favor the products, and the reaction rate must be fast enough to form them in a reasonable time. – These two conditions depend on …
Read More »How to Predict the Outcome of acid-base reaction
– In this subject, we will discuss How to Predict the Outcome of acid-base reaction. How To Predict the Outcome of acid-base reaction – The following table gives the approximate pKa values for a range of representative compounds. – While you probably will not be expected to memorize all of the …
Read More »