Formulae and Chemical Equations Flashcards
What are the 3 types of chemical bonding
Ionic, Covalent, Metallic (Metallic is a bond between only Metals)
What is Ionic Bonding
Element involved - Metal and Non-Metal
Particles involved - Ions (charged particles e.g. positive/negative)
Description - Electrostatic force of attraction between oppositely charged ions (They form ions to get full outer shells)
Example - Sodium Chloride (NaCl) or Iron Sulphide (FeS)
What is Covalent Bonding
Element involved - Non-Metal and Non-Metal (could also be bonded with same element like O₂)
Particles involved - Molecules (Simple-small and Giant-big)
Description - Atoms share electrons to achieve full outer shells
Example - Water (H₂O) or Glucose (C₆H₁₂O₆)
What are Formulae used to represent
Compounds (shows the number of each type of atom in a molecule of a substance by writing the number in subscript after the symbol)
Number in Chemical Subscript
1 - Mono 2 - Di 3 - Tri 4 - Tetra 5 - Penta 6 - Hexa
Hydrochloric Acid
HCl
Nitric Acid
HNO₃
Sulphuric Acid
H₂SO₄
Ammonia
NH₃
Methane
CH₄
Phosphoric Acid
H₃PO₄
Carbonic Acid
H₂CO₃
6 Diatomic Elements
Hydrogen (H₂) Oxygen (O₂) Nitrogen (N₂) Chlorine (Cl₂) Iodine (I₂) Bromine (Br₂)
Compounds that end in -ide
Contain only 2 elements (e.g. Sodium Oxide Na₂O; Zinc Sulphide ZnS; Calcium Nitride Ca₃N₂)
OR…
Contain a Hydroxide Group (e.g. Sodium Hydroxide NaOH)
Compounds that end in -ate
Contain more than 2 elements, one of which is oxygen (e.g. Potassium Nitrate KNO₃; Calcium Carbonate CaCO₃)
How do you work out the formulae of Ionic Compounds
Make sure the positive and negative charges are the same.
OR…
Use Criss-Cross Method
Take charge of the 2 elements and swap the numbers (e.g. Al ³+ and O ²+ becomes Al₂O₃)
What method can you use to “guess” the charge of an element’s ion
Group 1 - 1 Group 2 - 2 Group 3 - 3 Group 4 - 4 Group 5 -3 Group 6 - 2 Group 7 - 1 Group 8/0 - 0
Hydrogen
H +
Sodium
Na +
Potassium
K +
Lithium
Li +
Silver
Ag +
Ammonium
NH₄ +
Magnesium
Mg 2+
Calcium
Ca 2+
Copper(II)
Cu 2+
Zinc
Zn 2+
Iron(II)
Fe 2+
Lead
Pb 2+
Barium
Ba 2+
Aluminium
Al 3+
Iron(III)
Fe 3+
Fluoride
F -
Chloride
Cl -
Bromide
Br -
Iodide
I -
Hydroxide
OH -
Nitrate
NO₃ -
Hydrogen Carbonate
HCO₃ -
Hydride
H -
Oxide
O 2-
Sulfide/Sulphide
S 2-
Carbonate
CO₃ 2-
Sulfate/Sulphate
SO₄ 2-
Nitride
N 3-
How to balance a Chemical Equation
Calculate how many atoms of each element are on each side of the equation (left side - reactants; right side - products)
If numbers are the same then the equation is balanced
If not then add a co-efficient in front of the formulas (this adds more substance not changing the formula otherwise that would make a different substance)
Start with Unbalanced Elements that only appear in one substance on each side of the equation.
Repeat until equation is balanced.
What substances do you write a Solid state symbol underneath (write (s) as a subscript on the right of the element/compound)
All metals (e.g. Mg, Ca, Zn, Ni, Li etc...) Metal Oxides (e.g. Na₂O, MgO) Metal Carbonates (e.g. CaCO₃, Li₂CO₃) Carbon (C)
What substances do you write a Liquid state symbol underneath (write (l) as a subscript on the right of the element/compound)
H₂O
Mercury (Hg)
Fe (when extracted from its ore iron oxide)
SO₃
What substances do you write a Gas state symbol underneath (write (g) as a subscript on the right of the element/compound)
Steam - H₂O H₂ O₂ Cl₂ N₂ CO (Carbon Monoxide) CO₂ SO₂ HCl - Hydrogen Chloride CH₄ (Methane) NO₂ NO
What substances do you write an Aqueous state symbol underneath (write (aq) as a subscript on the right of the element/compound)
Aqueous means dissolved in water, ions are free to move
All ionic compounds (e.g. MgCl₂, NaCl, FeCl₃)
All acids (e.g. HNO₃ - Nitric Acid, H₂SO₄ - Sulphuric Acid, HCl - Hydrochloric Acid)
Alkaline Solutions (e.g. NaOH, KOH)
Nitrate
Sulfate
