How bonding and structure are related to the properties of substances Flashcards
What does the amount of energy needed to change state from solid to liquid and liquid to gas depend on?
The strength of the forces between the particles of the substance
What does the nature of the particles involved depend on?
The type of bonding and the structure of the substance
The stronger the forces between the particles…
The higher the melting point and boiling point of the substance
What are the limitations of the simple model of solid liquid and gas
- No forces
- All particles are represented as spheres
- The spheres are solid
What is the structure of an ionic compound
Giant ionic lattice in which there are strong electrostatic forces of attraction in all directions between oppositely charged ions
Melting and boiling point of ionic compounds
High MP and BP-ionic bonds are strong, lots of energy needed to break the strong electrostatic force of attraction
What happens when ionic compounds are melted or dissolved in water
They conduct electricity because the ions are free to move and so charge can flow.
cant conduct when solid because the ions are fixed in place
What are substances that consist of small molecules usually ? Do they have high or low boiling points?
Gases or liquids with low melting and boiling point
What is overcome when a small molecule is melted
Intermolecular forces (NOT THE COVALENT BONDS) They are weak in these substances
What increases with size of the molecules
Intermolecular forces so the larger molecules have higher melting and boiling points
Do small molecules conduct electricity?
No because the molecules do not have an overall electric charge
Are polymers large or small molecules?
Very large
How are the atoms in polymers linked to other atoms?
By strong covalent bonds
Why are polymers solid at room temperature?
Because the intermolecular forces are strong between polymer molecules
Substances that consist of giant covalent structures are what
Solids with very high melting points
