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Atom and molecule

WHAT IS FORMULA UNIT MASS OR FORMULA MASS?

The compounds which are formed by ions are called ionic compounds. In general, cations are made by metals and anions are made by non-metals. So, it can be understood as compounds made by metals and non-metals are ionic compounds. Examples – Al2(SO4)3, CaCl2, K2SO4, KNO3, CaCO3, NaCl, MgCl2 etc. Read more – Law of Conservation of …

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How do you Write Chemical Formula for an Ionic Compound?

Rules for writing a chemical formula  Write down the symbols of the ions (cation and anion) involved. Write the symbol of cation first (L.H.S) followed by the symbol of anion (R.H.S.). Write the valency of each ion. Interchange the valencies of the ions and write as the subscript. Write them close together and ignore ‘1’ …

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RULES FOR WRITING A CHEMICAL FORMULA OF SIMPLE COMPOUNDS

Chemical formula is a symbolic representation of a molecule’s composition. It indicates – (a) the elements that are present in the compound and (b) the ratio of these elements in the compound. A chemical formula is also called molecular formula. The symbols in the molecular formula tell us about the elements and the subscript tells …

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Problems / Numericals based on Mole Concept (Atomic Mass/ Molar Mass/ Avogadro number)

Formulas in brief –               Mass = Molar mass x Number of moles  Number of moles = Given number of particles / Avogadro number      Number of particles = (Given mass / molar mass) x Avogadro number          (from 1 and 2)  If one carbon atom has a mass of 12 atomic mass units and one magnesium atom has …

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Mole Concept – Introduction, Importance and Formulae

Introduction  The structure of matter can be one of the following – atoms → molecules → bulk compound or element atoms → bulk element atoms → ions → bulk ionic compound It clearly shows that the masses that are measured in the laboratory are masses corresponding to large numbers of tiny atoms or molecules. Logically …

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Atoms and Molecules / Counting Matter- Summary, Introduction

 Summary – ♦ Laws of  Chemical Combination – (a) Law of Conservation of Mass – Mass can neither be created nor be destroyed in a chemical reaction. (b) Law of Constant Proportions – In a chemical substance, the elements are always present in definite proportions by mass. ♦ Dalton’s atomic theory – All matter is composed …

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List of Polyatomic Ions and Charges

 Simple ions – The ions which are formed from single atom carrying a positive or negative charge are called simple ions or mono-atomic ions. Example – Na+, Cl–, O-2, Al+3, N-3(nitride), Mg+2, Ca+2, Cu+2, Fe+2etc. Polyatomic ions -Polyatomic ions or compound ions are molecules formed from groups of atoms bonded together that carry a positive …

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IONS – Anions and Cations

Atoms are neutral; they contain the same number of protons (positive particles) and electrons (negative particles). When the numbers of these subatomic particles are not equal, the atom is electrically charged and is called an ion i.e. ions are electrically charged atoms with extra electrons or missing electrons. It means ions are formed when atoms lose or gain …

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Dalton’s Atomic Theory of Matter , Drawbacks and Importance

Read First – Law of Conservation of Mass Law of Definite Proportions / Constant Composition Mole Concept – Importance and formulas       John Dalton FRS (6 September 1766 – 27 July 1844) John Dalton was an English chemist, physicist, and meteorologist. He is best known for proposing the modern atomic theory and for his research into colour blindness, sometimes referred …

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How to solve Problems based on Law of Definite Proportions / Constant Composition

Read first – What is Matter? What is its Characteristics? States of Matter Law of Conservation of Mass Problems based on Law of Conservation of Mass Law of Definite Proportions / Constant Composition Mole Concept – Importance and formulas Problem 1 : One mole of  V2O5 contains 5 moles of oxygen atoms, as it is clear from …

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Law of Definite Proportions / Constant Composition

Read First – What is Matter? What is its Characteristics? States of Matter Law of Conservation of Mass Problems based on Law of Conservation of Mass The law of definite proportions or constant composition states that – “All pure samples of a particular chemical compound, the constituent elements are always combined in the same proportions …

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Laws of Chemical Combination – Law of Conservation of Mass

Read more – What is matter? What is its Characteristics? States of matter Mole Concept – Importance and formulas There are four laws of chemical combination. They are – 1. The law of conservation of mass 2. The law of constant (definite) proportions 3. The law of multiple proportions 4. The law of reciprocal proportions …

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