10 (easy) Flashcards
Concentration change (1)
- (Reaction), Concentration of _ increase/decrease, ep shift to _
Pressure change (2)
- Num of moles of gaseous reactants >=< num of moles of gaseous products
- Increase/decrease in pressure, ep shift _
Temperature change (3)
- Increase in pressure favors endothermic reaction/ decrease in pressure favors exothermic reaction
- Forward reaction is _
- Increase/ decrease in temp cause ep to shift to _
Why catalyst no effect on ep?
Catalysts increase forward and backward reactions to the same extent
Temperature changes on Kc (4)
- Increase in temp favors endo reaction/ decrease in temp favors exo
- Forward reaction is endo/exo
- Increase/decrease in temp causes ep to shift to _
- Kc increases/decreases when temp increases/decreases
Le Chatelier’s principle
if reaction conditions of a system in eqm is changed, the ep of the system will shift in a way to reduce effect of the change
Add water case (solvent)
- Concentration of both products and reactants decease
- (Write Qc)
- The numerator(分子)/denominator decreases to a greater extent than the denominator/numerator, Qc increases/decreases
- Thus Qc<>Kc
- Ep shifts _
- More _ is formed, (observation)
Constant (l/s)
- Conc of _ is a constant
- Addition of _ does not affect conc of _, conc of all species in eqm system rains unchanged
- There is no effect on ep
- No obv change
Why use this color indicator?
-> pH range of color change falls on the steepest part of the titration curve
Deduce exo/endo:
- When temp increases/decreases, conc of _ increases/decreases
- Implying ep shift _
- As increase in temp favors _ rxn, forward rxn is _
chemical bonding: (exo/endo)
- The reaction involves breaking/forming of _ bond, hence rxn is endo/exo
TEMPERATURE have thermal contraction/expansion
Why is water neutral at all temperature?
as concentration of H+(aq) and OH-(aq) are the same
Why is Haber process (make NH3) a slow reaction?
a lot of energy is needed to break strong NN in N2 molecules and H-H bonds in H2 molecules
Why isn’t high pressure needed in contact process (remains at 1 atm)?
as the rate of conversion is already very high increasing pressure can only lead to small increase in percentage conversion but very high cost needed
Contact process equations
S + O2 -> SO2
2SO2 + O2 REVERSIBLE 2SO3
SO3 + H2SO4 -> H2S2O7
H2S2O7 + H2O -> 2H2SO4
What is dynamic equilibrium
rate of forward reaction equal to rate of backward reaction but not zero
Definition of Irreversible reaction
proceeds in one direction and goes to completion
Definition of reversible reaction
proceeds in either direction and never goes to completion
