Electrochemistry
- Alkanes (overview)
Structure & Bonding saturated: all C atoms are bonded to 4 atoms all C atom are sp3 hybridised non-polar simple molecular structures consisting of alkane molecules held together by weak VDW forces ...
- Alkenes (overview)
← Back to Alkenes Structure & Bonding unsaturated: contain C=C C atoms in C=C are sp2 hybridised non-polar simple molecular structures consisting of alkene molecules held together by weak VDW forces ...
- Chemical Bonding
NOTES: TYPES OF QUESTIONS: Determine Structure and Bonding Draw Dot-Cross Diagrams Determine Type of Bonding for Simple Molecules Predict/ Account for Physical Properties ...
- Determine Type Of Bonding For Simple Molecules
← Back to Chemical Bonding To determine the type of molecule (polar/ non-polar) and IMF, you will need these four steps: 1) Draw dot-cross diagram: 1 Determine the central atom and surrounding atoms. Central...
- Determine Structure & Bonding
← Back to Chemical Bonding Determine Structure: Structure Metals Giant Ionic Lattice Ionic Compounds Giant Ionic Lattice Covalent Compounds Giant/ Simple Molecule Structure Metal and Non-Metals...
Electrochemistry
Predict/ Account for Physical Properties
← Back to Chemical Bonding
Approach:
- Determine the type of substance (metal/ ionic/ covalent) and structure (giant metallic/ giant ionic/ giant covalent/ simple molecular)
- Determine bonding relevant to property
- Focus on that particular column to determine the bonding and factors that affect it.
Students tend to make mistakes when they try to pinpoint a factor without regards for the structure and bonding.
* Covalent bonds are also present in simple molecular structures. However, they are not broken during physical reactions (e.g. boiling, melting)
| Example: Work in Progress |
Simple Molecular Structure
To compare strength of intermolecular forces for two molecules:
- Check molar mass (Mr): larger Mr → larger e– cloud → more easily polarised → more extensive dispersion
- For molecules with similar Mr, check type of molecules (polar/ non polar) [learn how]
There are three possible cases:
Case 1 (both polar):
- Check for H-bonding: molecule with H-bonding will have higher bp/mp.
- If both have H-bonding, compare the extent of H-bonding i.e. no. of possible H-bond per molecule, presence of intra H-bonding that leads to less extensive inter H-bonding.
Case 2 (one polar, one non-polar):
- The polar molecule will always have higher bp/mp.
- pd-pd interactions stronger than dispersion.
Case 3 (both non-polar):
- Difference must be due to surface area.
- Increased branching → more spherical e– cloud → lesser area of interaction → less extensive dispersion
- Alkanes (overview)
Structure & Bonding saturated: all C atoms are bonded to 4 atoms all C atom are sp3 hybridised non-polar simple molecular structures consisting of alkane molecules held together by weak VDW forces ...
- Alkenes (overview)
← Back to Alkenes Structure & Bonding unsaturated: contain C=C C atoms in C=C are sp2 hybridised non-polar simple molecular structures consisting of alkene molecules held together by weak VDW forces ...
- Chemical Bonding
NOTES: TYPES OF QUESTIONS: Determine Structure and Bonding Draw Dot-Cross Diagrams Determine Type of Bonding for Simple Molecules Predict/ Account for Physical Properties ...
- Determine Type Of Bonding For Simple Molecules
← Back to Chemical Bonding To determine the type of molecule (polar/ non-polar) and IMF, you will need these four steps: 1) Draw dot-cross diagram: 1 Determine the central atom and surrounding atoms. Central...
- Determine Structure & Bonding
← Back to Chemical Bonding Determine Structure: Structure Metals Giant Ionic Lattice Ionic Compounds Giant Ionic Lattice Covalent Compounds Giant/ Simple Molecule Structure Metal and Non-Metals...