Effect of raising temperature on equilibrium constant?

In summary, Sulfuryl chloride (SO2Cl2) is a highly reactive gaseous compound that decomposes into SO2 and Cl2 when heated. This decomposition is endothermic and a sample of 3.509 grams of SO2Cl2 placed in a 1.00-liter bulb at 375 K will result in a total pressure of 1.43 atmospheres. The partial pressures of SO2, Cl2, and SO2Cl2 at equilibrium at 375 K can be calculated. The equilibrium constant for the decomposition of SO2Cl2 at 375 K can be expressed as Kp or Kc and its value can be calculated. Raising the temperature to 500 K will favor the end
  • #1
erik-the-red
89
1
1) Sulfuryl chloride, SO2Cl2, is a highly reactive gaseous compound. When heated, it decomposes as follows.

SO2Cl2(g) <===> SO2(g) + Cl2(g)

This decomposition is endothermic. A sample of 3.509 grams of SO2Cl2 is placed in an evacuated 1.00-liter bulb and the temperature is raised to 375 K.

(a) What would be the pressure in atmospheres in the bulb if no dissociation of the SO2Cl2(g) occurred?

(b) When the system has come to equilibrium at 375 K, the total pressure in the bulb is found to be 1.43 atmospheres. Calculate the partial pressures of SO2, Cl2, and SO2Cl2 at equilibrium at 375 K.

(c) Give the expression for the equilibrium constant (either Kp or Kc) for the decomposition of SO2Cl2(g) at 375 K. Calculate the value of the equilibrium constant you have given, and specify its units.

(d) If the temperature were raised to 500 K, what effect would this have on the equilibrium constant? Explain briefly.


This was an AP Chemistry question in 1983.

I was able to do parts a-c without a problem.

Raising the temperature favors the endothermic reaction. It was given in the information that this reaction is endothermic.

But, what does "favor the endothermic reaction" mean? I want to say that there is a stress placed on the system that can be alleviated by the partial pressures of the products increasing (ie. [tex]K_p[/tex] increases) How can I say this more briefly?
 
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  • #2
the reaction requires energy to drive the foward reaction, so if you were to increase the amount of energy available to the system, you would have relatively more decomposition yield.
 
  • #3



As the temperature increases, the equilibrium shifts towards the endothermic reaction, resulting in an increase in the partial pressures of the products and a corresponding increase in the equilibrium constant (Kp or Kc). This is due to the stress placed on the system, which is relieved by the increase in product concentrations. At a higher temperature of 500 K, the equilibrium constant would also increase, further favoring the endothermic reaction.
 

1. How does raising temperature affect the equilibrium constant?

As temperature increases, the equilibrium constant for a reaction will either increase or decrease, depending on whether the reaction is exothermic or endothermic. In general, an increase in temperature will shift the equilibrium in the direction that absorbs heat, in order to counteract the temperature change.

2. What is the relationship between temperature and equilibrium constant?

The relationship between temperature and equilibrium constant is described by the Van't Hoff equation, which states that the equilibrium constant is directly proportional to the ratio of the forward and reverse reaction rate constants, with the ratio increasing as temperature increases.

3. Why does raising temperature affect the equilibrium constant?

Raising temperature affects the equilibrium constant because it changes the amount of energy available for the reaction to occur. This can lead to changes in the rates of the forward and reverse reactions, ultimately resulting in a change in the equilibrium constant.

4. Is the effect of raising temperature on equilibrium constant different for all reactions?

No, the effect of raising temperature on equilibrium constant is not the same for all reactions. The direction and magnitude of the change in equilibrium constant will depend on the enthalpy (ΔH) and entropy (ΔS) of the reaction, as well as the temperature at which the reaction occurs.

5. Can equilibrium constant be used to predict the effect of temperature on a reaction?

Yes, the equilibrium constant can provide information about how a reaction will be affected by changes in temperature. By understanding the thermodynamics of the reaction, it is possible to predict whether an increase or decrease in temperature will cause the equilibrium constant to shift in a particular direction.

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