AQA Combined Chemistry 5.2 Flashcards
Revision for Paper 1
What is the chemical formula of Buckminsterfullerene?
C(60)
What element are all fullerenes made from?
Carbon
Describe the structure of fullerenes
Mostly hexagonal rings of carbon. Can be spherical or cylindrical in shape
Give three examples of giant covalent structures
Diamond, graphite, silicon dioxide
What do the following symbols represent?
a) s
b) l
c) g
d) aq
a) solid
b) liquid
c) gas
d) aqueous
Do metals have high or low melting points and boiling points?
High melting and boiling points
Diamond and graphite are made out of a single element. Name this element.
Carbon
Can molecules conduct electricit? Give a reason for your answer
No, because they have no overall electric charge
What type of bond exists between metals and non-metals in a compound?
Ionic Bond
What is the name for the forces that exist between ions in an ionic bond?
Electrostatic forces
What type of bonding exists in metallic elements and alloys?
Metallic bonding
In which type of bond are electrons shared?
Covalent bond
In which type of bond are electrons transferred?
Ionic bond
What type of bond exists in non-metal elements and compounds?
Covalent Bond
What is the name for the electrons that are free to flow in metallic bonding?
Delocalised electrons
When atoms gain or lose electrons to become ions, they will have the electron structure of what group of elements?
Noble gases
Describe how sodium and chloride bond to form sodium chloride
1) The sodium atom loses one electron to become a sodium ion
2) The chlorine atom gains one electron to become a chloride ion
3) The positive sodium ion is attracted to the negative chloride ion to form sodium chloride
What charge do metal ions have?
Metal ions are positive
What charge do non-metal ions have?
Non-metal ions are negative
Small molecules contain what type of bonds?
Covalent bonds
Describe the structure and bonding of an ionic compound
a) ionic bonding
b) giant structure of ions
c) lattice structure
d) oppositely charge ions held together by electrostatic forces acting in all directions
Why do small molecules usually have relatively low melting and boiling points?
a) they have weak forces between molecules (intermolecular forces)
b) it is the intermolecular forces that are overcome, not the covalent bonds, when the substance boils.
What is the relationship between the forces between particles and a substance’s melting and boiling points?
The stronger the forces between particles, the higher the melting and boiling points
What charge do the ions of elements in the following groups have?:
a) Group 1
b) Group 2
c) Group 6
d) Group 7
a) +
b) 2+
c) 2-
d) -
Describe the structure and bonding in a metal
a) metallic bonding
b) strong metallic bonds
c) giant structure of metal atoms in regular pattern
d) outer shell electrons are delocalised
Why do molten or aqueous solutions of ionc compounds conduct electricity?
Ions are free to move so charge can flow
What are the limitations of the following diagrams to represent ionic structures?
a) dot and cross
b) ball and stick
a) dot and cross - doesn’t show the structure of the ionic compound, the size or arrangement of ions
b) ball and stick - suggests gap between ions which aren’t in fact there
Why do ionic compounds have high melting and boiling points?
Because a lot of energy is needed to break the many strong bonds
What type of bonds exist in large molecules, such as plymers?
Covalent bonds
Describe how the arrangement of atoms makes pure metals soft
a) atoms arranged in layers
b) layers slide easily over each other
What are the limitations of using the particle models below to represent solids, liquids and gases?
a) no forces between the particles are shown in the diagram
b) all particles are represented by spheres
c) all the spheres are solid and inelastic
What state are most polymers at room temperature? Why?
a) solid
b) because they are large molecules, with strong intermolecular forces, hence relatively high melting and boiling points
What bonds must be overcome in order to melt or boil giant covalent structures?
The strong covalent bonds between the atoms
Descrobe the structure and bonding of Diamond
a) giant covalent structure
b) each crbon forms four covalent bonds with other carbon atoms
Describe the properties of Diamond
a) hard
b) very high melting point
c) doesn’t conduct electricity
What happens to the size of intermolecular forces as the size of molecules increase?
The size of intermolecular forces increase (hence higher melting and boiling points for larger molecules)
Why are metals good conductors of heat and electricity?
They have delocalised electrons that can carry the charge or transfer energy
What are cylindrical fullerenes called and why are they useful?
a) nanotubes
b) they have a high length to diameter ratio making them useful for nanotechnology, electronics and materials
Describe how the arrangement of atoms in an alloy makes alloys harder than pure metal
a) different sized atoms
b) layers disorted
c) atoms can’t easily slide over each other
Describe the structure and bonding of Graphite
a) giant covalent structure
b) each carbon forms three covalent bonds with other carbon atoms
c) forms layers of hexagonal rings
d) no covalent bonds between layers
e) one electron from each carbon atom is delocalised
What is graphene?
A single layer of graphite
Name two uses of graphene
Used in electronics and composites
