Mutiple Choice - Equilibrium state

In summary, the first conversation discusses a stoppered flask containing benzene, iodine, and air at equilibrium at 298K. It states that the pressure of the vapour phase is not constant, evaporation of the liquid continues, the colour of the liquid phase can change, and the mass of the solid iodine is not constant. The second conversation discusses an equilibrium represented by the equation Heat + H2O(l) <-> H2(g) at T = 373K and P = 101kPa. It states that adding boiling water to the system would increase its total volume, removing water vapour from the system would decrease its total volume, and cooling the system would decrease its temperature. The third conversation presents four
  • #1
ChemRookie
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1. Consider a stoppered flask containing benzene, iodine, and air, which has reached equilibrium at 298K. Which one of the following statements converning the system at equilibrium is true?
a) The pressure of the vapour phase is not constant
b) Evaporation of the liquid continues.
c) The colour of the liquids phase will change
d) The mass of the solid iodine is not constant.

2. Consider the equilibrium represented by the following equation:
Heat + H2O(l) <----
-----> H2)(g) in which T = 373K, P= 101kPa
a) The total volume of the system is increased.
b) Boiling water is added to the system
c) Water vapour is removed from the system.
d) The system is cooled.

3. Consider the following systems:
a) a container that is half-filled with alchol, soppered, and allowed to stand for several days
b) crystals of KMnO4 that are dissolved in water until the water becomes a uniform purple colour and a constant amount of crystal remains in the container.
c) an ice cube in a beaker of water in a normal classroom
d) moth balls that are placed in an empty flask that is then stoppered and allowed to stand for several days
Which of the above are in an equilibrium state?
i) a and b only
ii) a, b, and d only
iii) b and c only
iv) a, b, c and d

Thanks
 
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  • #2
FYI, I've just deleted the response to this thread because it contained a complete solution.

Please, whether you are receiving or giving help here, read the notice at the top of this Form entitled https://www.physicsforums.com/showthread.php?t=4825.

Now, Chem Rookie, what do you think about these questions?
 
  • #3
for your question! I would like to provide the following response:

1. The correct answer is b) Evaporation of the liquid continues. At equilibrium, the rate of evaporation is equal to the rate of condensation, so there is a constant exchange of molecules between the liquid and vapour phases. This means that evaporation is still occurring, even though the overall amount of liquid and vapour remains the same.

2. The correct answer is d) The system is cooled. At equilibrium, the forward and reverse reactions are occurring at equal rates, so there is no net change in the amount of water present. However, changing the temperature of the system can affect the equilibrium position, and in this case, cooling the system will shift the equilibrium towards the reactant side, resulting in more liquid water and less water vapour.

3. The correct answer is iv) a, b, c and d. All of the systems described are in equilibrium, as there is no net change in the amount of substance present. In system a, although the alcohol is evaporating, it is also condensing at the same rate. In system b, the dissolved KMnO4 is in equilibrium with the solid crystal, and the solution remains a constant purple colour. In system c, the ice is melting at the same rate as it is freezing, maintaining a constant amount of ice in the beaker. In system d, the moth balls are sublimating and depositing at equal rates, resulting in no net change in the amount of solid present.
 

1. What is an equilibrium state?

An equilibrium state is a state in which the forward and backward reactions of a chemical reaction occur at equal rates, resulting in no overall change in the concentrations of reactants and products.

2. How is equilibrium state achieved?

Equilibrium state is achieved when a chemical reaction is allowed to proceed until the concentrations of reactants and products reach a constant value, and the forward and backward reactions occur at equal rates.

3. What factors can affect the equilibrium state of a reaction?

The concentrations of reactants and products, temperature, and pressure can all affect the equilibrium state of a reaction. Changes in these factors can shift the equilibrium towards either the reactants or products.

4. Can an equilibrium state be disturbed?

Yes, an equilibrium state can be disturbed by changes in the concentration of reactants or products, temperature, or pressure. These changes can cause the equilibrium to shift towards the reactants or products until a new equilibrium state is reached.

5. How is equilibrium state represented in a chemical equation?

Equilibrium state is represented by a double arrow (⇌) in a chemical equation, indicating that the reaction can proceed in both the forward and backward directions.

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