C 5 Flashcards
(31 cards)
what does percentage yield equation
actual/theoretical x 100
what are the reasons for not getting 100% yield
reactants may not all react - reaction being very slow or reached equilibrium
may be side reactions meaning products are wasted
some products may be lost
whats the equation for atom economy
mr of desired product/sum of mr of all reactants
what are problems with low atom economy
less sustainable as it uses more resources
more waste products have to be disposed
conversion from dm cubed to cm cubed
/1000
equation for concentration(g/dm3)
mass/volume (dm3)
or
moles/volume =(dm3)
concentration equation (mol/dm3)
amount of solute in mol / volume of solution in dm3
equation for mass mr mol
mass = mol x mr
what are the three steps of titration
rough, accurate and repeat
how to calculate titre
final reading - initial reading
equation for molar volume
molar volume = gas vol/ number of mol
volume of gas equation
24 x mol = Volume dm3
how do you measure rate of reactions and what are the equations for it
measure how fast reactants are used up or how fast products are formed
quantity of products formed/ time taken
quantity of reactants used/ time
how do you measure the rate of reaction from a gas
draw a tangent to a specific time, we can calculate rate of reaction at this time by finding the gradient of the tangent
When considering how a condition will affect the rate of reaction, what do you have to consider
the frequency of collisions
energy of the particles
what conditions affect the rate of reaction and why`
temperature - particles have more energy and move faster so more frequent collisions
concentration - more particles means more collisions
surface area - more area for collisions to take place
presence/ absence of a catalyst - more successful and frequent collisions
what does it mean for a reaction to be at equilibrium
the concentration and reactants are staying at the same rate
what conditions need to be met for equilibrium to take place
the reaction needs to take place in a closed system
how do you know which way equilibrium lies
if there are more products than reactants equilibrium lies right and vice versa
whats le Chateliers principle
when change of conditions of a reversible reaction, position of equilibrium will shift to counteract this change
what can equilibrium be affected by
pressure
temperature
concentration
N2 + 3H2 (reversible) – 2NH3 (-92kj/mol)
what will increasing pressure do to equilibrium
what will increasing temp do to this reaction
what will decreasing concentration of N do
pressure - equilibrium moves right
temp - left
conc - right
how do you know if the reactions endo/ exothermic
if the total energy is - the forward reaction is exo
what is oxidation and reduction in terms of oxygen
oxidation - gain of oxygen
reduction - loss of oxygen
