Chemistry Formulas & Equations PDF

## 5.1 Names and Formulae of compounds ### Empirical formula - Simplest whole number ratio of atoms of each element in a compound ### Molecular formula - Actual ratio of atoms of each element present in a compound ### Metal + Non-metal - Metal + non-metal + ide. - eg Magnesium oxide ### No...

## 5.1 Names and Formulae of compounds ### Empirical formula - Simplest whole number ratio of atoms of each element in a compound ### Molecular formula - Actual ratio of atoms of each element present in a compound ### Metal + Non-metal - Metal + non-metal + ide. - eg Magnesium oxide ### Non-metal + Non-metal - Lower group number of non-metal + ide - Exception: NH₃ - eg Carbon dioxide - Hydrogen present: Hydrogen non-metal-ide ### H₂O - 2 hydrogen, 1 oxygen - Chemical formula tells you ratio of atoms. ### NH₃ - Structural formula shows how its bonded. ### Deducing formula by combining power | | Valency | | :-- | :-------- | | Al | G₃= 3 | | G₁ | 1 | | G₂ | 2 | | G₃ | 3 | | G₄ | 4 | | G₅ | -3 | | G₆ | -2 | | G₇ | -1 | - Al = G₃ = 3 + S = G₂ = 8 → Al₂S₃ - Aluminium Sulfate ## 5.2 Equations for chemical reactions - Diatoms must be written as molecules. - Carbonate = (CO₃)^2- - Sulfate = (SO₄)^2- - Hydroxide = (OH)^- - Nitrate = (NO₃)^- - When these ions form a compound with a metal, write the metal first. ### Calcium Carbonate - Ca²⁺ + CO₃^2- → CaCO₃ ### NaOH + HCl → NaCl + H₂O - Balanced = Equal number of each atom on either side. ### Solid: (S), Liquid: (l), Gas: (g), Aqueous: (ag) = State Symbol ### Aluminium (s) + Copper (II) oxide (s) -> Aluminium oxide (s) + Copper (s) - Al + CuO -> Al₂O₃ + Cu - So the start should also be 2. - 2Al + CuO -> Al₂O₃ + Cu - So it should also start with 3. - 2Al + 3CuO -> Al₂O₃ + Cu - You can only put 3 infront of the whole thing but that makes the left have 3 Cu but the right have only 1. - 2Al + 3CuO -> Al₂O₃ + 3Cu