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prop
3
but
4
Non renewable examples;
coal, coal seam gas and crude oil
Non-renewable impacts;
negative = explosive, deforestation, greenhouse gases
positive = higher energy content, cheaper
Renewable examples;
bio gas, bio diesel and bioethanol
Renewable impacts;
positive = local, less greenhouse gases, bio degradable
negative = lower energy content, high water usage, expensive
exo - the enthaply of....
the products is less than the enthaply of the reactants
endo - the enthaply of...
products is higher than the enthaply of the reactants
complete combustion
O2 is excess and clean blue flame
incomplete combustion
O2 is limiting and yellow flame
electrolyte
solution with ions that conducts electricity
salt bridge
connect the half cells internally and maintains electrical neutrality
primary cells...
cannot be recharged as the electrodes are consumed
secondary cells...
can be recharged by connecting them to an external source
fuel cells...
convert the chemical energy of a fuel into electricity through a reaction with oxygen
cell being recharged means...
you swap the products and reactants around
density formula
D=m/v
galvanic cells are....
a spontaneous reaction where chemical energy goes to electrical energy
electron flow...
negative to positive
inert elements
carbon, platinum, gold and mercury
Fuel cells advantages =
efficient as they convert chemical energy to electricity, hydrogen fuel cells only produce water and heat as by products with no greenhouse gases, can be used in variety of fuels
fuel cells disadvantages =
require constant fuel supply, expensive, storage and safety of hydrogen fuel
∆H =
Hproducts - Hreactants = kJmol -1
what is pressure?
force exerted on an area
OIL RIG
Oxidation is loss of e-
Reduction is gain of e-
In a galvanic cell the anode is _____ and the cathode is _____
negative, positive (ANOX and REDCAT)
How to increase the rate of an reaction?
increase temp, surface area, concentration and pressure
when a catalyst is added...
it decreases the activation energy by creating an alternative reactive pathway and thus the proportion of successful collisions increases.
Reversible reactions occur...
in closed systems and cannot achieve 100% yield
What is the equil constant only affected by?
temp
K>10^4
equil contains more products
K < 10^-4
the equil contains more reactants
Q>K
reverse reaction
Q<K
forward reaction
As pressure increases...
volume decreases
If pressure is increased, and mole ratio is 1:2
forwards reaction is favored
If pressure is increased, and mole ratio is 2:1
reverse reaction is favored
When concentration of reactants increase
forward reaction
When concentration of reactants decrease
reverse reaction
When con of products increase
reverse reaction
When con of products decrease
forward reaction
when coeffs are halved...
Kc = square root
when reaction is reversed...
Kc = 1/number
when coeffs are doubled...
Kc^2
when coeff reversed and halved...
1/square root
Electrolytic reactions are...
- non-spontaneous
- energy is required
- anode is positive
- cathode is negative
what happens in discharge?
galvanic cells producing electrical energy
what happens in recharge?
electrolytic cells producing chemical energy
Q =
charge (C)
I =
current (A)
T =
time (s)
F =
96500 C
n(e-) = Q / F
Q = n(e-) x F
adding more reactant shifts the reaction..
to the RHS thus a forward reaction
adding more products shifts the reaction...
to the LHS thus a reverse reaction
by increasing the volume (decreasing pressure) it shifts...
where the most particles are
when volumes is decreased and pressure is increased..
shifts the side with less particles
adding a catalyst and inert gas...
has no effect on the equil
when temp increases, for exo...
LHS
when temp increases for endo...
shifts the RHS
adding H2O (dilution)
direction with most particles
removing a product...
shifts to RHS thus forward reaction
