Flashcards
Chemical equilibria
Flashcards do conjunto (28)
- 1What are the factors which affect the position of an equilibrium?•Temp
•Pressure
•Conc - 2What is a dynamic equilibrium?•A reversible reaction where:
•The rate of the forward reaction is equal to the rate of the backward reaction.
•Macroscopic properties of reactants and products are kept constant - 3What is the difference between a homogenous mixture and a heterogenous mixture?•Homo - same phase
•Hetero - different - 4What is the advantage of a homo over a hetero?•In a homo, reactants and products uniformly mix.
•In hetero, they dont - 5What is Le chateliers principle?•If any of the macroscopic properties change, the system will adjust itself to nulify or minimize that change.
- 6What are the key principles in a molar fraction?•Applies to homogeneous mixture only.
•No units
•Total sum = 1 - 7What is avagadro's law?•In a mixture of gases, for a fixed temp and pressure. if the gaseous volumes are equal, the gases contain the same number of molecules.
- 8What is the relationship between the pressure exerted by a gas and the no. of molecules it has?•Directly proportional
(PRESSURE IS DIRECTLY PROP TO MOLECULES) - 9What is the only factor which the pressure exerted by a gas depends on?•The number of molecules it has.
NATURE OF GAS IS INSIGNIFICANT. - 10What is Dalton's law of pressure?•The total pressure of a mixture of gases is equal to the sum of pressures of each individual gas if that gas were to occupy the respective volume at a given temperature
- 11What is meant by the term partial pressure?•The pressure exerted by a gas when it alone occupies the whole volume under the same conditions of temperature.
- 12How can we define Kc?•The ratio of product concentration
•to the ratio of reactant concentration
•each raised to the power of its stiochiometric coefficient. - 13What type of law is Kc referred to as?•law of mass action.
- 14In terms of the rate constant of the forward and backward reaction, how is Kc defined?Kc = k1/k2
- 15In an endothermic equilibrium, what is the relationship between Kc and the temperature?•ENDO:
Temperature is directly proportional to the equilibrium constant. - 16In an exothermic equilibrium, what is the relationship between Kc and the temperature?•EXO:
Temperature is inversely proportional to the equilibrium constant. - 17Explain how increased temperature causes Kc to increase in an endothermic equilibrium?•Increased temperature causes K1 to increase.
•As Kc=K1/k2, as k1 increases, Kc will increase as well. - 18What factors do K1 and K2 depend on?•K1 - reaction rate of forward reaction (r1)
••K2 - reaction rate of forward reaction (r2) - 19What factors do r1 and r2 depend on?•temp
- 20How does increased temperature cause Kc to decrease in an exothermic equilibrium?•K2 increases
•According to Kc=K1/K2, Kc will decrease. - 21What is common to both K1 and K2 when temperature increases?•Either one will increase.
•When temp increases, K1 or K2 dont decrease. - 22What are the factors to be considered when writing the Kp expression?•All components in same phase
•Solids are not included as their activity is constant.
•H2O is not seen.
•Conc of H2O remains constant. - 23How is Kp defined?•Ratio of product of partial pressure to the products.
•Ratio of product of partial pressure.
•Each is raised to the power in the stiochiometric equation. - 24What is the relationship between Kp and Kc?•At a constant temperature, the numerical value of Kp is equal to the numerical value of Kc.
- 25In an exothermic equilibrium, in terms of entropy, how would increased temp affect the equilibrium constant?•In exo, entropy of surrounding is positive.
•Increased temp would cause surrounding entropy to be less positive.
•Thereby, total entropy decreases.
•Hence, equilibrium constant decreases. - 26In an endothermic equilibrium, in terms of entropy, how would increased temp affect the equilibrium constant?•In endo, surrounding entropy is negative.
•Increased temp would cause surrounding entropy to be less negative.
•Thereby, the total entropy increases.
•Hence, the equilibrium constant increases. - 27As the equilibrium constant and entropy increase, what can be said about the rate of the reaction?•As the equilibrium constant and entropy is greater, the rate of the reaction is greater as well.
- 28Define Kpc?•(concentration of the solute in first solvent)/concentration of the solute in second solvent.
Informações
- Descrição
- A-Level Chemistry FlashCards sobre Chemical equilibria, criado por Jio Jenassi em 08-06-2016.
- Criado por
- Jio Jenassi
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