The Mole Concept, Chemical Formula and Equation

Activity 3.2 (Textbook) – Chemistry Form 4 Chapter 3 (The Mole Concept, Chemical Formula and Equation)

Activity 3.2:Studying the concepts of relative atomic mass and relative molecular mass by analogyMaterials: 36 washers, one 5 cm bolt, five nuts, one flat magnet and stringsApparatus: Two-pan balance(A) Relative atomic mass based on the carbon-12 scaleProcedure: 1. You are given three models of carbon-12 atom. Calculate the number of washers required to form each … Read more

Chemical Equation

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 Molecules

Formula of Molecule In SPM, you need to know the formulae of the following molecules Fluorine  F2 Hydrogen chloride  HCl Chlorine  Cl2 Hydrogen bromide  HBr Bromine  Br2 Hydrogen iodide  HI Iodine  I2 Nitric oxide  NO Carbon dioxide  CO2 Nitrogen dioxide  NO2 water  H2O Nitrous oxide  N2O Ammonia  NH3 Tetrachloromethane  CCl4 Sulphur trioxide  SO3 Hydrogen sulphide … Read more

Formula of Ionic Compounds

Chemical Formlula of Ionic Compounds 2 Requirements to form the formula of an ionic compound Have at least 2 types of ions that contain opposite charge. The amount of positive charge/charges must be equal to the amount of negative charge/charges in the compound. Example 1 – If the Charge of the Positive Ions = Charge … Read more

Percentage of Mass

Percentage of Composition of a Compound To find the percentage of composition of a substance means to find the percentage of mass of each element in the molecule of the substance to the mass of the molecule. The percentage of mass of an element can be determined by the following equation: RAM = Relative atomic … Read more

Molecular Formula

Molecular Formula The molecular formula of a substance is the chemical formula that gives the actual number of atoms of each element in the substance. A molecular formula is the same as or a multiple of the empirical formula.  For example, the empirical of carbon dioxide is CO2 and the molecular formula is also CO2. Whereas, … Read more

Empirical Formula

Empirical Formula The empirical formula of a substance is the chemical formula that gives the simplest whole-number ratio of atoms of each element in the substance. Empirical = information gained by means of observation, experience, or experiment. Example: Chemical Substances Molecular Formula Empirical Formula Glucose C6H12O6 CH2O Water H2O H2O Carbon Dioxide CO2 CO2 Benzene … Read more

Chemical Formulae

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