P1 V2 Flashcards
why do giant ionic lattices have high melting and boiling points
due to the high amount of energy needed to break the strong electrostatic forces
what happens at the melting point
melting and freezing
what happens at the boiling point
boiling and condensing
what are the properties of small molecules
they are usually gases or liquids which have low boiling and melting points because the intermolecular forces need to be overcome not the covalent bonds
the strength of the intermolecular forces increase with the size but because they are small they have low melting and boiling points
They do not conduct electricity due to not having an overall electric charge
what are the properties of polymers
polymers are long molecules, this means it has a stronger intermolecular force meaning a higher boiling and melting point. this means that they are normally solids at room temp, polymers have a lower boiling and melting point that giant covalent and ionic structures
what are the properties of giant covalent structures?
they have very high melting and boiling points. this is because each atom is connected by a stong covalent bond which is needed to be overcome in order to melt ot boil the element. One example of this is diamond where each carbon atom has a strong covalent bond with 4 other carbon atoms.
what are the properties of metals and alloys and what are done to pure metals that are too soft by themselves?
metals are normally have giant structures with strong metallic bonding meaning they have high melting and boiling points, this is due to the strong electrostatic force between the negative delocalised electron and the positive metal ions. In pure metals, atoms are in layers allowing it to be malleable, this means that they are normally too soft for their uses so they are mixed with other metals to make a metal alloy this distorts the layers and makes its harder to slide over each other, meaning it is less malleable
why are metals good conductors of heat and electricity
because each metal atom has a delocalised electron, this leads to the structure having a sea of delocalised electrons which can carry charge. When it comes to heat, energy can be carried through the sea of delocalised electrons meaning it is a good thermal conductor
what is avogadro’s constant
6.02 X 10^23
what is the limiting reactant in a chemical equation and why is it common?
a limiting reactant is the substance that runs out before the other, the other is in excess to ensure the limiting reactant is completely used up.
what is the equation for concentration and what are the units ?
concentration (g/dm^3) = mass (g) / volume (dm^3)
what is OILRIG
oxidation is loss ( of electrons)
reduction is gain (of electrons)
what are ions?
ions are what is formed when an atoms loses or gains electrons to gain a full ouet shell
what type of substance (metal, non metal) are negative and positive ions?
Metals lose an outer shell electron to form a positive ion
Non-metals gain an outer shell electron to form a negative ion.
what are the charges of ions?
if you gain an electron is -1
if you lose an electron its +1
what is the name for structure of an ionic compound and how does this affect the electrostatic forces? How does this affect melting and boiling points?
Giant ionic lattices have negative and positive electrons packed together so the strong electrostatic forces between the negative and positive ions are all around. This means that it has a high melting and boiling points because it takes lots of energy to overcome these bonds
why can molten or dissolved ionic compounds carry charge?
because the ions are free to move and can carry charge. The ones that can dissolve in a solution, the ions seperate and are free to move meaning they can carry electrical charge
what is a covalent bond?
a bond between two nonmetal atoms which is joined together by strong electrostatic forces, which makes them very strong. They share the amount of atoms needed to fill up the outer shell of both atoms.
