AS Chemistry Flashcards
isotope
each atom of element has same no of protons, different number of neutrons
mass number
total number of protons and neutrons
atomic number
number of protons,
ammonium
nh+4
hydrogencarbonate
hco3-
manganate
mno4-
dichromate
cr2o7-2
phosphate
PO4-3
relative isotopic mass
the mass of an atom of an element relative to one twelfth of the mass of an atom of carbon-12
one mole
amount of substance, contain same no of particles as 12g of carbon 12.
no of moles
no of things/6.02x10^24
yield
actual/max theroticaly
why is yield never 100%
side reactions can occur
reactions may not be complete
reaction can be reversible.
atom economy
desired product mR/sum of Mr of all
gases at room temp
mol x 24dm^3
if not at room temp
pV=nRT
standard solution
solution of known concentratiion, made in voncial flasks
how do you prepare a standard solution?
1)zero balance and weigh mass to small beaker
2)dissolve in small amount of distilled water.
3)using funnel, transfer to volumetric flask,
4)rinse with distilled water, and make it to the line.
concentration
moles/volume of solution.
acids
proton donors
can be strong/weak depending on dissociation.
bases
protons acceptors
some are soluble, and release OH
acid+metal
salt+water
acid+metal hydroxide
salt+water
acid+metal carbonate
salt+water+co2
hydrous salt
salt containing water, which is heated to release.
oxidiation number
pure elements=0
flurione=-1, O=+2
oxygen=.2, peroxides=-1
Cl=-1, Fl or O=1
disproportion reaction
same reaction is oxidised and reduced
oxdising agent
gets reduced
electron acceptors
reducing agent
gets oxidised
reduction of others
ionic bonding
metals and non mentasl
structure of ionic
giant ionic lattice need large amount of energy to overcome electrostatic forces.
electron conductivty as can conduct when molten as particles are mobile.
covalent bonding
happens between non metals
electrostatic attraction between shared pair of electrons and nuceli of bonded atoms.
dalative covalent
involve share pair of electrons, where only one pair supplies electrons.
linear
2 bond pairs=180
trignoal planer
3 bond pairs=120
bent
2 bond, and 1 lone-117.5
tetracadal
4 bond paairs=109.5
pyramdial
3 bond and 1 lone=107
octacherdal
6 bond=90
london forces
electron density is uneven, so temp dipole. more electrons=stronger induced dipole so is stronger.
happens in all molecules, only intermolecular between non polar.
permanent dipole
occur between polar molecules
opposite ends of each pole attract each other.
hydrogen bonds
lone pair attracted to H+
polar
different electronegativty, +-more share.
polar-has to be any of these
different molecules
central has a lone pair.
polar
not symmetrical
bonds dont cancel.
first ionisation energy
energy required to remove any electron from each atom in mole of gaseous to form +1 ions.
x->x+e
nuclear charge
more protons, more attraction so electron removed
atomic radius
larger atomic weaker nucleus attraction
electron shielding
electrons
ionisation energy increases due to
large atomic
greater shielding
Higher nuclear(this is outweighed by other 2)
dips in Al and P
due to change in subshell.
and less energy, as due to less repulsion, from orbital of 2 then one.
period 2 is higher ionisation energy
dip for boron=higher sub shell
0=first paired electron
period 2 melting points
Li and Be
decrease in ionic radius
more delocalised electrons
B and C
b=3 covalent bonds
c=4 covalent
N, O, F, Ne needs less energy to break forces
group 2
lose electrons to form 2+
reducing agents
reactivity increases as go down
antacids
neutralise soils
group 2=reactivity increases as go down
increase of atomic
more shielding
less attraction
electrons lost easily
halogens
solid=simple covalent lattices
f2=pale yellow
c2=pale green
br2=red brown
i2=shiny gra
why does oxidising decrease as you go down
higher atomic
higher shielding
weaker attraction
test of chlorine
add small of dilute nitric acid, to remove carbonate. add silver nitrate=white
bromine-cream
iodine=yellow
bond enthalpy
one mole of covalent bond broken in gas state.
enthalpy change
bonds broken-bonds formed
hess law
if reaction can take place by two routes, enthalpy is same.
Formation=products-reactants
Combustion=reactants-products.
enthalpy change of neutrallisation
enthalpy change for reaction between acid and base to produce one mole of water under standard conditions.
enthalpy change
heat change at constant pressure
One mole of covalent bonds broken in gas state
formation
one mole of compound formed from constituent elements in standard states and conditions.
combustion
one mole of substance in standard states burned in excess of O2 under standard conditions.
collision theroy
particles must collide for reactions to occur.
need
=correct oreniation
sufficent energy
dynamic equillbrium
reactants to products
closed
same concentration
factors = pressure, temperature, and concentration
temperatyre
+ endothermic=increase temp favours
- exothermic=decrease temp favours
test for ammonium
add NaOH=warm
test with damp red litmus should go blue
test for carbonate
add dilute acid, should be efferceveness
test for sulfate
add barium nitrate, and white
order for tests
carbonate, sulfide, halidie
