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Writing Chemical Equations A Balance Equation According to the Law of Conservation of Mass, atoms cannot be created or eliminated in the process of chemical reaction. Therefore, the amount of atom of each element before reaction must be equal after reaction. Example:Balance the following chemical equations: Mg + O2 → MgO CuO + … Read more
Formula of Ions Ionic compounds made up of positive ions and negative ions. To write the formula of an ionic compound, we need to know the symbol and charge of the ions in the compound. Positive ions that you need to know in SPM form 4 chemistry: Ion Symbol Ion Symbol Potassium K+ Calcium Ca2+ … Read more
Each element is represented by its own chemical symbol. In an element, the chemical formula represents the atoms in the molecule. The chemical formula tells us: the types of atoms or ions in the compound, the number of atoms or ions in the compound, For example, the chemical formula for ethene is C2H4. This shows … Read more
Molar Volume of Gas Equal amount of gas occupies same volume of space. Molar volume of a gas is defined as the volume occupied by one mol the gas at certain condition At room temperature(25ºC) and pressure (1 atm), one mole of any gas occupies a volume of 24 dm³ (24 000 cm³ ) At … Read more
Molar Mass The mass of one mole of atoms is its relative atomic mass in grams, and is called a molar mass. A Molar mass is the mass of a substance containing the Avogadro Constant of particles. Element Relative atomic mass Mass of 1 mol of particle Molar Mass Hydrogen 1 1 g 1 g … Read more
A mole is defined as the amount of substance which contains the Avogadro Number of particles. The Avogadro Number (or Avogadro Constant) is defined as the number of atoms in 12 g of the carbon-12 isotope, which is equal to 6.02 x 1023. 1 mole = 6.02 x 1023 Example:1 mol of atoms = 6.02 x … Read more
https://youtu.be/IjtBbEkse1g?list=PLP7MKjUAZ-wuAQxBnhzg24xQxK7QV-imQ Relative Mass The relative mass of an object is the comparison of the mass of the object to the mass of a standard object. Relative Atomic Mass Relative Atomic Mass The relative atomic mass (Ar) of an element is the average mass of one atom of the element when compared with 1/12 of the … Read more
We have learnt that electrons occupy orbits with definite energy level of an atom, as suggested by Neils Bohr. These orbits with definite energy level are known as the shell. Every single shell is capable of holding up to certain amount of electrons. The first shell can hold up to two electrons. This is called … Read more
History of Development of the Model of Atom Table below shows the scientists that contribute to the development of the Model of Atom. John Dalton Five main points of Dalton’s Atomic Theory All matter is composed of extremely small particles called atoms. All atoms of a given element are identical, having the same size, mass, … Read more
Matter exists in 3 states of matter, namely, solid state, liquid state and gaseous state. Characteristics of Matter in Solid, Liquid and Gaseous State Arrangement of Particles Solid Particles are arranged in an orderly manner and close to one another. Liquid Particles are not arranged in order. The space between particles is moderately large. Gas The … Read more