everything chemistry paper 1
what are ionic compounds made from
charged ionic particles that make a giant lattice
do ionic substances have a high or low boiling point
high
why do ionic substances have a high boiling point
electrostatic forces of attraction act in all directions which require a lot of energy to overcome
what effects the boiling point of ionic substances
the difference in charge
properties of ionic compounds
giant lattice
name the ions
strong electrostatic forces of attraction
high mp/bp
requires a lot of energy to break
conduct electricity when molten or aqeous
properties of metallic bonding
giant structure of metal atoms
sea of delocalised electrons
strong metallic bonds
high mp/bp requires a lot of energy to overcome
can conduct electricity
properties of simple covalent
low mp/bp
gas/liquid at room temp
weak intermolecular forces
intermolecular forces increase as mr increases
cant conduct electricity
properties of diamond
giant lattice
4 carbon bonds covalently
very high mp/bp
cant conduct electricity
very hard
properties of graphite
giant structure
3 carbon bonds covalently
conduct electricity
very high mp/bp
soft and slippery
no covalent bonds between layers
properties of graphene
conductor of electricity
one layer of graphite
strong covalent bonds
high tensile strength
first fullerene
buckminsterfullerene
uses of fulleres
lubricants
deliver pharmaceuticals
adv disadv of dot and cross diagram
+show which atom the electrons came from
-give no information about shape or relative size
adv disadv of ball and stick
+shows relative size and arrangement
-ions are too widely spread and no detail on electrons being transferred
3d space filling
+shows relative size and tightly packed
-confusing to see and no detail on where electrons came from
test for chlorine
bleaches litmus paper
test for carbon dioxide
turns limewater cloudy
test for oxygen
glowing splint is relited when put into the test tube
test for hydrogen
squeaky pop when lit splint is put into test tube
difference between transition metals and alkali
transition are harder
transition are denser
transition are higher boiling point
transition form coloured compounds
transition form different ions
alkali metals react with oxygen quicker
why was mendeleevs periodic table accepted
because he left space for atoms that were discovered later on
each group fit a certain trend
who was james chadwick and when was his discovery
nuclear model
1932
who was niels bohr and what was his discovery
atomic model
1913
who was ernest rutherford and when was his discovery
alpha scattering
1909
who was jj thompson and when was his discovery
plum pudding
1897
pros and cons of hydrogen fuel cells
+abundant resourves
no harmful pollutants
last longer than batteries
-hard to store
flammable
energy from fossil fuels
expensive to modify
what does a fuel cell do
converts chemical energy to electrical
what is the anode and cathode in a fuel cell
anode is negative cathode is positive
why is there solution in a fuel cell
so ions can move through it
how do fuel cells work
hydrogen enters anode compartment and is then oxidised by the anode
electrons pass through wire to cathode were oxygen enters through cathode compartment
hydrogen ions move through electrolyte
react to make water which leaves through outlet
electrons release energy
reaction at anode in a fuel cell
2H(2) -> 4H+ +. 4e-
reaction at positive electrode in fuel cell
O(2) + 4H+ + 4e- -> 2H(2)O