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I thought it would be interesting for everyone to share the most tricky questions they've seen over their mcat studying.
I'll start off:
If 2 gases react with each other to form 1 gas in an equilibrium reaction, how does the addition of a noble gas, different identity from the gases already present, shift the equilibrium?
Answer: there is no shift, despite the increase in total pressure, because the noble gas does not appear in the equilibrium expression for that equilibrium reaction. The partial pressures of the original gases stay the same.
In contrast, when artificially increasing pressure, by decreasing volume, you are increasing all of the reactants and products' partial pressure. If A+B-->C, all are gases, and you decrease volume(increase pressure), you increase the partial pressure of A,B and C. Now, since there are 2 components on the left side getting increased in contrast to 1 component on the right being increased, the equilibrium shifts to the right as per L'chatlier.
I'll start off:
If 2 gases react with each other to form 1 gas in an equilibrium reaction, how does the addition of a noble gas, different identity from the gases already present, shift the equilibrium?
Answer: there is no shift, despite the increase in total pressure, because the noble gas does not appear in the equilibrium expression for that equilibrium reaction. The partial pressures of the original gases stay the same.
In contrast, when artificially increasing pressure, by decreasing volume, you are increasing all of the reactants and products' partial pressure. If A+B-->C, all are gases, and you decrease volume(increase pressure), you increase the partial pressure of A,B and C. Now, since there are 2 components on the left side getting increased in contrast to 1 component on the right being increased, the equilibrium shifts to the right as per L'chatlier.
