4.2.2 How bonding and structure are related to the properties of substances Flashcards
What are the three states of matter?
Solid, liquid, and gas.
At what points do melting, freezing, boiling, and condensing occur?
Melting and freezing occur at the melting point. Boiling and condensing occur at the boiling point.
How are particles represented in the simple model of matter?
Particles are represented as small, solid spheres.
What does the amount of energy needed for a state change depend on?
It depends on the strength of the forces between particles.
What happens to the melting and boiling points if the forces between particles are stronger?
The melting and boiling points are higher.
(HT only) What are the limitations of the simple model of matter?
It does not show forces between particles. Particles are represented as solid, inelastic spheres. The model does not accurately depict particle interactions.
What are the state symbols in chemical equations?
(s) = Solid
(l) = Liquid
(g) = Gas
(aq) = Aqueous solution
Why are state symbols used in chemical equations?
To show the states of matter for substances involved in a reaction.
What is the structure of ionic compounds?
They have a regular giant ionic lattice.
Why do ionic compounds have high melting and boiling points?
Because of the strong electrostatic forces of attraction between oppositely charged ions, which require a lot of energy to break.
When do ionic compounds conduct electricity?
When they are molten or dissolved in water, as the ions are free to move.
What are the states of substances made of small molecules?
They are usually gases or liquids with relatively low melting and boiling points.
What forces are overcome during melting or boiling of small molecules?
Weak intermolecular forces, not covalent bonds.
How do intermolecular forces change with molecule size?
Larger molecules have stronger intermolecular forces, leading to higher melting and boiling points.
Why don’t substances made of small molecules conduct electricity?
Because their molecules do not have an overall electric charge.
What is the structure of polymers?
They consist of very large molecules with atoms linked by strong covalent bonds.
Why are polymers solid at room temperature?
Because the intermolecular forces between polymer molecules are relatively strong.
How can polymers be identified?
By diagrams showing their bonding and structure.
What are giant covalent structures?
Solids with very high melting points where all atoms are linked by strong covalent bonds.
What are examples of giant covalent structures?
Diamond, graphite, and silicon dioxide.
What needs to be overcome to melt or boil substances with giant covalent structures?
The strong covalent bonds between atoms.
How can giant covalent structures be recognized?
From diagrams showing their bonding and structure.
What is the structure of metals?
Metals have a giant structure with strong metallic bonding.
Why do metals have high melting and boiling points?
Due to the strong metallic bonds.
Why can metals be bent and shaped?
Because their atoms are arranged in layers that can slide over each other.
Why are alloys harder than pure metals?
The layers of atoms are distorted, preventing them from sliding over each other easily.
Why are metals good conductors of electricity?
Because delocalized electrons can carry electrical charge through the metal.
Why are metals good conductors of heat?
Because energy is transferred by delocalized electrons.
