What is the best method to classify a chemical substance
Classification
Methods
Chemical Substance
Chemical substances are elements, compounds or mixtures, they can be metals or non-metals. A pure chemical compound is a chemical substance that is composed of a specific set of molecules or ions (Bradford, 2003).
Chemicals can be classified by their structure, uses, physical properties, radiological properties, or other factors (Cdc.gov, 2023).
Atomic bonding (Washington.edu, 2023)
Covalent bonding - Bonding between two non metals, when the valence electrons from one atom are shared between two or more particular atoms.
Metallic bonding - Bonding between two metals, when the valence electrons are delocalised, constantly moving between atoms, they have a lattic structure
Ionic bonding - Bonding between a metal and non-metal, involves transferring valence electrons from one atom to another
Covalent Continuous Network - A covalent bonding, in a lattice structure, they are different from normal covalent bonds as they have high melting points and bonds
Method for type of bonding
200 degrees celcius melting point
Less
Covalent Bonds
More
Electricity conductor?
No
Yes
Conducts electricity in solution or molten form
Metallic Bonds
No
Yes
Continuous Covalent Network
Ionic Bonding
Different Structure Types
Covalent Molecule
Lattice Structure
Metallic Lattice
Covalent Network
Covalent Bonds
Ionic Lattice
Covalent Bonds
Usually high melting and boiling points, hard and brittle, and poor conductors of electricity (with the exception of graphite).
Usually low melting and boiling point (intermolecular forces weak), strong bonds, poor electric conductivity (electrons are localised)
Usually high melting and boiling points (strong electrostatic forces), brittle and can conduct electricity when molten or solution form (ions are free to move)
Usually high melting and boiling points,
good conductors of heat and electricity,
malleable and ductile (delocalized electrons)
A repeating three-dimensional arrangements of ions or atoms in a crystal
Physical properties
Potential experiments
Solubility test
Conductivity test
Melting point test
Hammer tests
Precipitation Reaction Test
Metallic Compounds: Luster, good conductors of electricity, and malleable and ductile.
Ionic compounds: Solid at room temperature, high melting and boiling points, conduct electricity when dissolved in water or molten.
Covalent Compounds: Solid/Liquid/Gas, low melting and boiling points, poor conductors of electricity.
Element: Pure substance consisting of one type of atom (Pdesas.org, 2020).
Compound: Pure substance consisting of two or more different atoms (Pdesas.org, 2020).
Mixture: Two or more different substances not chemically combined (Pdesas.org, 2020).
Possible Limitations
Time: Limits the amount of tests able to be run to determine the unknown substance
Safety/Risk Assessment
Make sure you are wearing the necessary safety equipment, including safety goggles, a lab coat or apron, and gloves appropriate for the pH of the acid you are working with.
Exercise caution when handling glassware, such as burettes and pipettes, as it is fragile and can break easily.
Be careful when handling with acids to prevent any potential spills.
Observing physical properties