c2 bonding structure and the properties of matter Flashcards
(50 cards)
1
Q
How can a particle change state?
A
- putting in or taking out energy:
putting in - heating. eg melting and boiling requires energy to break forces of attraction in solid
taking out - cooling. eg freezing and condensing reforms forces of attraction - stronger forces of attraction = more energy to break forces, higher MP
2
Q
particle arrangement in solids
A
- particles close together with little space between, in regular pattern
- fixed shape, particles vibrate
- fixed volume, hard to compress
3
Q
particle arrangement in liquids
A
- close together with little space between, free to move/flow over each other
- no fixed shape, fits container
- fixed volume, hard to compress
4
Q
particle arrangement for gases
A
- widely spaced and free to move
- no fixed shape, fill container
- no fixed volume, easy to compress
5
Q
limitations of the particle model of states of matter
A
- presents all particles as solid spheres. particles are different shapes and not solid
- assumed that there are no forces between particles. forces have major impact on MP and BP
6
Q
match the different types of bonding to the reacting elements involved
A
ionic - metal and non metal
covalent - non metal and non metal
metallic - metal and metal
7
Q
what should you get after drawing diagram for ionic bonding
A
atoms with mismatch dots/crosses in brackets with charge and number of the ion
8
Q
what should you get after drawing diagram for covalent bonding
A
overlapping circles with mismatch dots/crosses in intersection (energy level diagram)
- OR no circles (dot and cross diagram)
- OR lines (stick diagram)
9
Q
structure of ionic compounds
A
- form giant 3D structures: giant ionic lattice
- strong electrostatic forces of attraction (ionic bonds) in all directions, sometimes no shown in diagram
- each ion is surrounded by oppositely charged ions
10
Q
properties of ionic compounds
A
- high MP and BP as lots of heat energy needed to break electrostatic forces of attraction
- cannot conduct electricity when solid as ions are held in place by electrostatic forces of attraction. when melted of dissolved in water, ions are free to move and carry charge
11
Q
pros and cons of dot and cross diagram
A
- dots and crosses: clear where electrons are coming from
- dont tell us 3d arrangement of molecule
- doesnt tell us sizes of atoms
12
Q
pros and cons of two-dimensional stick diagram
A
- covalent bond is stick: cannot tell which electron came from which atom
- dont tell us size of atoms
- dont tell us shape of molecule
13
Q
pros and cons of three dimensional stick diagram
A
- tells us shape of molecule
- doesnt tell us movement of electrons
- shows empty space
14
Q
pros and cons of ball and stick model for lattices
A
- shows ions in 3d
- shown as spaced apart when ions are actually close together
- only show tiny part of giant lattice, impression that they are much smaller than they actually are
15
Q
pros and cons of space filling diagram for lattices
A
- shows how closely packed they are
- may be difficult to see 3d layers
- only show tiny part of giant lattice, impression that they are much smaller than they actually are
16
Q
what is a double/triple covalent bond and give examples
A
when atoms require 2/3 more electrons, so share 2/3 pairs of electrons
double eg oxygen, co2
triple eg nitrogen
17
Q
examples (on spec) and properties of small covalent molecules
A
- low MP and BP, gas or liquid at room temp, as little energy needed to overcome weak intermolecular forces (not covalent bonds!)
- as size increases, intermolecular forces increase
- do not conduct electricity, as they have no overall charge
18
Q
properties and examples of giant covalent molecules
A
- millions of covalent bonds
- solid at room temp, high MP and BP
diamond, silicon dioxide, graphite
19
Q
properties of diamonds and link to structure
A
- hundreds of carbon atoms each bonded to four other carbon atoms
- very hard due to lots of strong covalent bonds
- high MP and BP as lots of energy needed to overcome strong covalent bonds
- cannot conduct electricity as there are no free electrons
20
Q
properties of silicon dioxide and link to structure
A
- silicon and oxygen covalently bonded
- high MP and BP as lots of energy needed to break strong covalent bonds
21
Q
properties of graphite and link to structure
A
- carbon atoms each bonded to three other carbon atoms in hexagonal rings
- soft and slippery as hexagons form layers with no covalent bonds between, used as lubricants
- high MP and BP as lots of energy needed to overcome strong covalent bonds
- only three electrons per carbon atom used in bonds - one is delocalised per atom. good conductor of electricity and heat as delocalised electrons carry charge/heat
22
Q
allotropes of carbon
A
diamond
graphite
graphene
fullerenes
23
Q
properties of graphene and link to structure
A
- single layer of graphite, one atom thick
- good conductor of electricity as delocalised electrons carry charge
- very strong due to lots of strong covalent bonds
- high MP and BP as lots of energy needed to overcome strong covalent bonds
24
Q
what are fullerenes
A
hollow balls or closed tubes, ususally hexagonal, can also be 5 or 7
25
first fullerene discovered
buckminsterfullerene
- 60 carbon atoms
- hollow sphere
- rings of 6 or 5 carbon atoms
26
uses of fullerenes
- deliver drugs in body as they can form around molecules
- lubricants in machines to reduce friction between moving parts
- catalysts to speed chemical reactions
27
what are carbon nanotubes and what are properties
fullerenes shaped into cylinders with very high length to diameter ratio
- high tensile strength so can be stretched
- good conductor of electricity as delocalised electrons carry charge
- good conductor of heat
28
uses of carbon nanotubes
- reinforce material eg in high end tennis rackets
29
what is a polymer and what are their properties
- very large molecule with strong covalent bonds
- double covalent bond of monomers become single to join together
- solid at room temp as lots of energy needed to overcome relatively strong intermolecular forces between polymer molecules
30
how to draw a polymer
31
structure and bonding of metals
- metals consist of giant structures of atoms arranged in regular layers
- outer electrons are delocalised, meaning metal atoms are positive ions. strong electrostatic forces between, metallic bonds
- metallic bonds are very strong
32
properties of metals and link to structure
- high MP and BP as lots of energy required to overcome strong metallic bonds
- good conductors of heat and electricity delocalised electrons carry charge and thermal energy
- malleable as layers of atoms can slide over each other
33
problem of metals and solution
some pure metals eg copper, gold, iron, aluminium are not hard enough to use, need to be harder.
make an alloy:
mixture with other metals, meaning different sizes of atoms distorts layers, making them harder to slide over each other.
34
different particles and their diameters
coarse / dust / PM10
2.5 x 10^-6 and 1 x 10^-5 or
2 500nm and 10 000nm
fine / PM2.5
1 x 10^-7 and 2.5 x 10^-6 or
100nm and 2500nm
nano
1 x 10^-9 and 1 x 10^-7 or
1nm and 100nm
35
describe surface area to volume ratio for particle sizes
as diameter decreases by 10 times, SA:Vol ratio increases by 10 times
meaning nanoparticles have huge SA:Vol ratio, so much smaller quantity of material needed compared to material with normal particle size, to get the same effect
36
uses and risks of nanoparticles
- useful for catalysts, medicine, electronics, deoderant, cosmetics
- however nanoparticles can be absorbed into body and enter cells, however effects are unknown and must be studied
37
compare structure of ionic compounds, simple covalent bonds, giant covalent structures
- atoms vs ions
- giant with strong forces vs small with weak forces
- non-metals sharing electrons vs metal and non-metal transferring electrons
38
why is buckminsterfullerene a good lubricant
it is spherical so will roll
39
how to tell if something is a mixture or compound from the percentages of its contents
variable percentage = mixture
fixed percentage = compound
40
what effect does density have when building something
- heaviness
- difficulty to install
41
how to write sa:vol ratio
1:n or n:1
42
alloys of copper and uses
bronze
- hardens copper with tin
- makes ornaments and medals
brass
- hardens copper with zinc
- carpentry
43
alloys of gold and uses
- silver copper, zinc
- jewellery: "carat" expresses purity. 24=100%, 12=50%, etc
44
alloys of iron and uses
steels are alloys of iron
- carbon and other metals
- high carbon steel: strong & brittle
- low carbon steel: soft & malleable
- stainless steel (chromium & nickel): hard & corrosion resistant
45
alloys of aluminium and uses
- copper, manganese, silicon
- aircraft bodies: stronger, lighter, corrosion resistant (than Al)
46
use of polyethene
plastic bags
47
how can you change conditions to make diff polymers
- temp
- pressure
- catalyst
48
use of nanoparticles in sun cream
better coverage
more protection from suns uv
49
how to calculate size different between particles in standard form
- divide prefix numbers
- subtract indices (must show as two individual steps)
- multiply
50
size difference b/w nanotparticles and atoms
nanos larger - size of a few hundred atoms
