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What is the best method to classify a chemical substance? - Coggle Diagram
What is the best method to classify a chemical substance?
Bonding
What is bonding?
chemical bonding is the formation of a bond between at least two atoms, molecules or ions to make up substances we see in everyday life
What are the types of bonding?
ionic
Ionic bonding happens when an atom transfers electrons to another, leading to the creation of cations and anions. There is a strong electrostatic attraction between cations and anions, which holds them together.
Properties
High melting / boiling point
Poor conductivity in solid state; good conductors in aqueous state
Crystal lattice structure
Brittle
covalent
Covalent bonding is when electrons are shared between atoms, to achieve a stable electron configuration. Atoms in a covalent bond share valence electrons.
Properties
Low melting / boiling points
Poor conductors
metallic
In metallic bonds, atoms share their valence freely, creating a sea of delocalized electrons that move freely.
Properties
Good conductors
Malleable & ductile
How to test if the substance is ionic, covalent or metallic?
Conductivity
No
Covalent
Yes
Solid form
Metallic
Liquid form
Ionic
Hammer test
Crushed into powder (brittle)
Ionic
Flattens out (malleable)
Metallic
Melting point
Ionic will have a much higher melting point than covalent
Safety measures
Proper lab attire (Goggles, lab coat, hair tied up, closed shoes etc)
Chemical reaction awareness
Safety equipment
Waste disposal
First aid
Eye protection
Glove usage
Don’t eat or drink anything
Personal hygiene
Always be supervised
Risk assessment
Various tests (not all included)
Sollubility
Method: Place substance in water and stir
Hammer test
Method: Place substance on a mat and crush with hammer
Results: Brittle / Malleable
Conductivity
In solid / aqueous form
Flame test
Purpose: Discover cation
Method: Coat wire in hydrochloric acid and dip in substance so it is coated. Hold over the Bunsen burner and observe
Results:
pH levels
Method: Place 3 rg substance in 50 ml of distilled water. Add in 3 drops universal indicator and stir
Use pH chart to match colour
Silver Nitrate
Purpose: Discover anion
Method: Combine a few drops of dilute nitric acid with the solution. Add a few drops of silver nitrate solution
Heating test
Boiling/melting point
