4.2.2🐚 Flashcards
What are the three states of matter?
Solid, liquid and gas
What takes place at the melting point?
Melting and freezing
What takes place at the boiling point?
Boiling and condensing
What does the particle theory help to explain?
Melting, boiling, freezing and condensing
What does the amount of energy depend on for a change of state?
The strength of the forces between the particles in a substance.
What is the relationship between forces and melting and boiling point? - why
The stronger the forces between the particles the higher the melting and boiling point as there is more energy required to overcome these forces.
What are limitations of the particle model?
No forces are shown, all particles are represented as spheres and that all the spheres are solid.
What are the state symbols?
S - solid
L - liquid
G - gas
Aq - aqueous
Describe the properties of ionic compound: (x3)
- Regular structures, giant ionic lattices. There are strong electrostatic forces of attraction in all directions between oppositely charged ions.
- High melting and boiling points as there are large amounts of energy needed to break many strong bonds.
- when melted or dissolved, ionic compounds conduct electricity because the ions are free to move so charge can flow.
Describe the properties of small molecules: (x3)
- Low melting and boiling points. this is because they have weak intermolecular forces that are overcome (not the covalent bonds) when the substance melts or boils.
- intermolecular forces increase with size of molecules. (Larger molecules have higher melting and boiling points)
- cannot conduct electricity as they have no overall electric charge.
Describe a polymer
Very large molecule, atoms are linked by strong covalent bonds. They have strong intermolecular forces and so are solid at room temperature
Describe giant covalent structures
Solids with high melting points.
Atoms are linked by strong covalent bonds, require a lot of energy to overcome and so are solid at room temperature.
Examples of giant covalent structures?
Diamond, silicon dioxide and graphite
What are the properties of metals?
Giant metallic lattice, strong metallic bonds. They have Hugh me,ting and boiling points which require loyd of energy to overcome so are solids at room temperature.
Describe the structure of a metal?
Atoms are arranged in layers, which means the layers can slide over each other and be bent into shape. Pure metals are too soft however and so are mixed with other meta,so to make alloys.
