Macromolecular substances Flashcards
What is a macromolecule?
A massive, covalently bonded molecule containing thousands of atoms
What is a lattice made up of macromolecules called?
Macromolecular lattice
What is a lattice made up of smaller molecules called?
Molecular lattice
How are chain and sheet macromolecular lattices held together?
Intermolecular forces
How are 3D macromolecular lattices held together?
Covalent bonds
What is the structure of diamond?
A macromolecular lattice, made up of carbon atoms that form four covalent bonds (tetrahedral arrangement). This makes diamond really hard
Those strong covalent bonds take a lot of energy to break and give diamond a very high melting point
It doesn’t conduct electricity as it has no free electrons or ions
What is the structure of graphite?
Forms three covalent bonds, creating sheets of hexagonal carbon atoms (trigonal planar arrangement)
Soft and slippery due to weak intermolecular forces between the layers (free to move over each other)
High melting point (lots of energy needed to break covalent bonds in the layers)
Conducts electricity (each carbon atom has a delocalised electron)
What are allotropes?
Structures where the atoms of the same element bond in different ways
Why do macromolecular solids have really high melting points?
Need lots of energy to break strong covalent bonds
What are some other macromolecular lattices?
Silicon and silicon dioxide (sand)
How are macromolecules represented?
Empirical formula
