Periodic Properties and Variations of Properties:- Physical and Chemical
- Periodic Properties and Variations of Properties:- Physical and Chemical
- Periodic Properties: Physical Properties
- Periodic Properties: Chemical Reactivity
- Relation Between Atomic Number for Light Elements (Proton Number) and Atomic Mass for Light Elements
- Periodicity on the Basis of Atomic Number for Elements
- Periodic Properties: Electronegativity
- Periodic Properties: Electron Affinity
- Periodic Properties: Ionisation Potential (Ionisation Energy)
- Periodic Properties: Metallic Character
- Atomic Size
- Chemical Bond
- Coordinate Bond
- Comparison of Electrovalent and Covalent Compounds
- Covalent (Molecular) Bond
- Covalent (Molecular) Bond
- Characteristic Properties of Electrovalent Compounds
- Structure of Electrovalent Compounds NaCl, MgCl2, CaO
- Concept of Electrovalent
- Formation and Properties of Ionic Compounds
Study of Acids, Bases and Salts
Analytical Chemistry:- Use of Ammonium Hydroxide and Sodium Hydroxide
- Analytical Chemistry
- Action of Alkalis (Naoh, Koh) on Certain Metals, Their Oxides and Hydroxides
- On Solution of Salts - Sodium Hydroxide on Ammonium Salts
- On Solution of Salts - Special Action of Ammonium Hydroxide on Solutions of Copper Salt
- Formation and Colour of Hydroxide Precipitated for Solutions of Salts of Ca, Fe, Cu, Zn and Pb
- On Solution of Salts - Colour of Salt and Its Solution
Mole Concept and Stoichiometry
- Molar Volume of a Gas at S.T.P
- Deduction of Simple (Empirical) and Molecular Formula from the Percentage Composition of a Compound
- Relationship Between Vapour Density and Relative Molecular Mass
- Refer to the Atomicity of Hydrogen, Oxygen, Nitrogen and Chlorine
- Avogadro’s Law
- Gay Lussac’s Law of Combining Volumes
- Mole Concept
- Percentage Composition
- Empirical Formula of a Compound
- Determination of Molecular Formula
- Chemical Equation
- Electrolytes and Non-Electrolytes
- Substances Containing Molecules Only, Ions Only, Both Molecules and Ions.
- An Elementary Study of the Migration of Ions
- Applications of Electrolysis
- Concept of Electrolysis
- Acids, Bases and Salts as Electrolytes
- Dissociation of Ions and Electrical Conductivity
- Substances Containing Molecules Only
- Substances Containing Ions Only
- Applications of Electrolysis - Purification of Copper
- Substances Containing Both Molecules and Ions
- Chemical Method - NaOH for Purifying Bauxite – Baeyer’s Process
- Dressing of the Ore
- Extraction of Aluminium
- Common Ores of Iron, Aluminium and Zinc
- Extracting Metals Towards the Top of the Activity Series
- Extracting Metals in the Middle of the Activity Series
- Extracting Metals Low in the Activity Series
- Extraction of Metals from Ore
- Reduction of Metallic Oxides
- Types of Elements: Non-metal
- Corrosion of Metals and Its Prevention
- Position of the Metals (Alkali Metals and Alkaline Earth Metals) in the Periodic Table
Study of Compounds
- Concept of Ammonia
- Properties of Ammonia
- Catalytic Oxidation of Ammonia as the Source of Nitric Acid
- Ammonia - Uses of Ammonia
- Burning of Ammonia in Oxygen
- Ammonia - Reactions with Hydrogen Chloride and with Hot Copper (Ii) Oxide and Chlorine
- Aqueous Solution of Ammonia
- Ammonia - Density and Solubility of Ammonia (Fountain Experiment)
- Ammonia - Manufacture by Haber’s Process;
- Ammonia - Laboratory Preparation
- Concept of Hydrogen Chloride
- Hydrogen Chloride - Acidic Properties of Its Solution
- Hydrogen Chloride - Reaction with Ammonia
- Hydrogen Chloride - Density and Solubility of Hydrogen Chloride (Fountain Experiment)
- Hydrogen Chloride - Preparation of Hydrogen Chloride from Sodium Chloride
- Method of Preparation of Hydrochloric Acid
- Precipitation Reactions with Silver Nitrate Solution and Lead Nitrate Solution
- Uses of Acetic Acid
- Chemical Properties of Acetic Acid
- Concept of Acetic Acid
- Concept of Ethanol
- Hydrocarbons - Alkynes
- Hydrocarbons - Alkenes,
- Hydrocarbons - Alkanes
- Simple Nomenclature
- Homologous Series of Carbon Compound
- Structure of Compounds with Single, Double and Triple Bonds
- Special Features of Carbon
- Organic Compounds
Take an example of the reaction of hydrogen and oxygen to form water:
2H2+ O2 → 2H2O.
The above reaction indicates that
(i) two molecules of hydrogen combine with one molecule of oxygen to form two molecules of water, or
(ii) 4 u of hydrogen molecules combine with 32 u of oxygen molecules to form 36 u of water molecules.
We can infer from the above equation that the quantity of a substance can be characterised by its mass or the number of molecules. But, a chemical reaction equation indicates directly the number of atoms or molecules taking part in the reaction. Therefore, it is more convenient to refer to the quantity of a substance in terms of the number of its molecules or atoms, rather than their masses. So, a new unit “mole” was introduced. One mole of any species (atoms,
molecules, ions or particles) is that quantity in number having a mass equal to its atomic or molecular mass in grams.
The number of particles (atoms, molecules or ions) present in 1 mole of any substance is fixed, with a value of 6.022 × 1023. This is an experimentally obtained value. This number is called the Avogadro Constant or Avogadro Number (represented by N0),named in honour of the Italian scientist, Amedeo Avogadro. 1 mole (of anything) = 6.022 × 1023 in number,
as, 1 dozen = 12 nos.
1 gross = 144 nos.
Besides being related to a number, a mole has one more advantage over a dozen or a gross. This advantage is that mass of 1 mole of a particular substance is also fixed.
The mass of 1 mole of a substance is equal to its relative atomic or molecular mass in grams. The atomic mass of an lement gives us the mass of one atom of that element in atomic mass units (u). To get the mass of 1 mole of atom of that element, that is, molar mass, we have to take the same numerical value but change the units from ‘u’ to ‘g’. Molar
mass of atoms is also known as gram atomic mass. For example, atomic mass of hydrogen=1u. So, gram atomic mass of hydrogen = 1 g.
It is a method of expressing the amount of a substance.
Take a pause and remember the various units of measurement.
Now, consider a human with a weight of 60Kgs. Why did we express it in Kgs and not in meters?
So basically, every measurement has magnitude with its SI unit. In this case, 60 was the magnitude and the SI unit was Kgs!
Atomically, we can measure the weight with the help of this mole concept.
Your body weight is inclusive of all the cells present inside your body. Likewise, One gram of element will have many atoms and its mass will be inclusive of all of them!
Like we discussed their molecular mass, now we will measure it in moles.
A mole is the chemist’s counting unit and 1 mole is equivalent to 6.022 × 1023 number.
Now let’s start with the denotation of the various term that will help us in solving the numerical -
|Denoted by||SI unit|
|Given mass||m||Grams (g)|
|Molar mass||M||Grams (g)|
|Given the number of particles||N||-|
|Avogadro number of particles||N0||-|
|Number of moles||n||Moles|
`"no. of moles" = "given mass"/"molar mass" = "given number of particles"/"given number of particles"`
`"n" = "m"/"M" = "N"/N_0`
Shaalaa.com | Atoms and Molecules (Mole Concepts)
The equations given below relate to the manufacture of sodium carbonate (Molecular weight of Na2CO3 = 106).
NaCl + NH3 + CO2 + H2O → NaHCO3 + NH4Cl
2NaHCO3 → Na2CO3 + H2O + CO2
To produce the mass of sodium hydrogen carbonate what volume of carbon dioxide, measured at STP would be required?based on the production of 21.2 g of sodium carbonate.
The percentage composition of a gas is Nitrogen 82.35%, Hydrogen 17.64%. Find the empirical formula of the gas. [N = 14, H = 1]