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# Kc watch

1. why does increasing the temperautre shift the eqm to the right and the value of kc increases for the question:

In the following equilibrium, Kc = 54.1 at a particular temperature. The equilibrium mixture was found to contain H2 at a concentration of 4.80 x 10-4 mol dm-3, and HI at a concentration of 3.53 x 10-3 mol dm-3.
H2(g) + I2(g) ⇌ 2 HI(g) enthalpy > 0

What effect would increasing the temperature have on the equilibrium position and Kc?

why would favouring the endothermic reaction lower the temperature
wouldn't the exothermic because it releases heat into the surroundings?

this is what i dont get?
2. (Original post by esmeralda123)
why does increasing the temperautre shift the eqm to the right and the value of kc increases for the question:

In the following equilibrium, Kc = 54.1 at a particular temperature. The equilibrium mixture was found to contain H2 at a concentration of 4.80 x 10-4 mol dm-3, and HI at a concentration of 3.53 x 10-3 mol dm-3.
H2(g) + I2(g) ⇌ 2 HI(g) enthalpy > 0

What effect would increasing the temperature have on the equilibrium position and Kc?

why would favouring the endothermic reaction lower the temperature
wouldn't the exothermic because it releases heat into the surroundings?

this is what i dont get?
In an endothermic reaction heat energy is converted into chemical potential energy and the temperature decreases.

Hence an equilibrium moving in the direction of endothermic change can reduce the effect of increased heat energy being applied.
3. (Original post by esmeralda123)
why does increasing the temperautre shift the eqm to the right and the value of kc increases for the question:

In the following equilibrium, Kc = 54.1 at a particular temperature. The equilibrium mixture was found to contain H2 at a concentration of 4.80 x 10-4 mol dm-3, and HI at a concentration of 3.53 x 10-3 mol dm-3.
H2(g) + I2(g) ⇌ 2 HI(g) enthalpy > 0

What effect would increasing the temperature have on the equilibrium position and Kc?

why would favouring the endothermic reaction lower the temperature
wouldn't the exothermic because it releases heat into the surroundings?

this is what i dont get?
When it says "into the surroundings", remember its a closed system so endothermic reactions tend to lower the temperature as they take in energy as the enthalpy change is positive, + .
Exothermic reactions release energy meaning they increase temperature, so if the forward reaction is exothermic then decreasing the temperature of the system would favour the forward reaction as more energy is released to restore the system to equilibrium.

So when it says enthalphy is >0 for the forward reaction, it means its positive, so its an endothermic reaction and an increase in temperature will favour the forward reaction as it takes in energy so reduces the temperature restoring equilibrium.

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Updated: February 20, 2018
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