chemistry in society Flashcards
feedstock
a reactant from which other chemicals can be extracted or synthesised
raw materials
what feedstocks are derived from
atom economy
the mass of the product you want as a percentage of the mass of the reactants used in the reaction
percentage yield
the mass of the product actually made compared to the mass of the product it is theoretically possible to make.
what is molar volume
volume of one mole of gas
what do particles require for reaction to occur
correct collision geometry and activation energy
colour change for starch indicator
colourless- blue black
the products in endothermic reactions have…. energy than the reactants
more
the products in exothermic reactions have…. energy than the reactnats
less
exothermic reactions …… heat to surroundings
loses
endothermic reaction…… heat form surroundings
absorbs
what is temperature
measure of the average kinetic energy of the particles in a chemical.
problems with a copper cup alcohol burning set up
evaporation of alcohol
heat lost to surroundings
non uniform distribution of heat
incomplete combustion
molar volume equation
V = N x Mv
enthalpy of combustion equations
Eh=CMΔT
Eh= ΔH x N
bond enthalpy
the energy needed to break on mole of bonds in a mole of gaseous molecules
hess’s law
the enthalpy change for any reaction is independent of the route,
provided the starting conditions and final conditions are the same
equillibrium
the point in a reversible system when the rate of the forward reaction equals the rate of the backwards reaction
le Chateliers principle
the position of the equilibrium in a chemical reaction will change to minimise the effect of any imposed change in the reaction
increase temperature
shifts to endothermic side
decrease temperature
shifts to exothermic side
add reactant or remove product
shift to the right
remove reactant add product
shit to left
increase pressure
shifts to reduce moles
decrease pressure
shifts to increase moles
if ΔH is negative the reaction is
exothermic
if ΔH is positive the reaction is
endothermic
retention factor
the distance travelled by the dot divided by the distance travelled by solvent front.
small polar molcules travel
further and faster
