chap 6 - balancing equation

• chemical nomenclature

  • naming ionic compounds

  - metals forms only positively-charged ion (cations) while non-metals form only negatively-charged ions (anions).

  - positive ions can only be attracted to the negative ions, they form ionic compounds.

  - strong electrostatic forces of attraction exists between the oppositely-charged ions

  - the ionic compounds formed are always electrically neutral which have no overall charge
• chemical nomenclature

  • naming ionic compounds

  - cations ions are named before anions. metals retain their elements names in compounds while non-metallic ions end with ´ide´

  - valency = no. of electrons an atom gains or loses to achieve a full valance shell
• chemical nomenclature

  • chemical formula of ionic compounds

  - hydroxide : OH-

  - nitrate : NO3-

  - carbonate : (CO3)2-

  - sulfate : (SO4)2-

  - ammonium : NH4+

  - zinc : Zn2+

  - silver : Ag+

  - hydride : H-

  - hydrogen : H+
• covalent substance

  • group 18 are known as noble gases
  • diatomic molecules (made up of 2 atoms only)

  > hydrogen gas : H2

  > nitrogen gas : N2

  > oxygen gas : O2

  • group 17

  > fluorine gas : F2

  > chlorine gas : Cl2

  > bromine : Br2

  > iodine : I2
• covalent substance

  • prefix

  > is used to represent the no. of atoms of a non-metal present in a covalent compound

  = mono : 1 no. of atoms of element present

  = di : 2 no. of atoms of element present

  = tri : 3 no. of atoms of element present

  = tetra : 4 no. of atoms of element present
• covalent substance

  • some have special names

  > ozone : O3

  > water : H2O

  > methane : CH4

  >ammonia : NH3

  >hydrochloride acid : HCl
• balancing chemical equations

  • reactants and the products must be that same
  • steps

  1. balance polyatomic ions

  2. balance metal

  3. balance non-metal

  4. balance hydrogen and oxygen

  • state symbol

  - (s) --> solid

  - (l) --> liquid

  - (g) --> gas

  - (aq) --> aqueous (soluble in water)