2H2 (g) + O2 (g) <---> 2H2O (g)
what is the likely magnitude of the equilibrium constant?
a) k < 10 ^-3
b) 10^-3<K<10^3
c)k=0
d)k>10^3
i know that choice c is incorrect because if k=o there would be no need to calculate equilibrium, but how would i go about narrowing down the other answers? thanks.
You have already eliminated c. Since we know this is a spontaneous reaction and occurs with explosions when the two gases are mixed, I wouldn't think a number as small as 0.001 (a) is appropriate so that leave b and d. b means somewhere between 0.001 and 1000, more than likely about <500 or so. That is a relatively small number as K goes, so I would pick >10^3 (d). We can make an educated guess if we look up delta Go for H2O liquid. My book lists -237.2 kJ/mol.
delta Go = -RTlnK = -237.2 kJ
Change that to J and we have
-237200 = 8.314*298*ln K.
Solve that for ln K = about 95 (you can do it on your calculator) and K = 3.8 x 10^41 which is a huge number. I would pick d. Check my reasoning.
thanks, i double checked and everything looks right. i'm going with answer d. thank you again!
To determine the likely magnitude of the equilibrium constant (K), we can utilize the stoichiometric coefficients in the balanced equation. The equilibrium constant expression for the given reaction is:
K = ([H2O]^2) / ([H2]^2 * [O2])
Considering the stoichiometry of the equation, the concentrations of H2O, H2, and O2 will all be in the denominator.
Since the balanced equation involves a significant amount of water vapor (H2O), which is typically present in high concentrations as a gas, the concentration of H2O will be relatively large compared to H2 and O2. This suggests that the numerator of the equilibrium constant expression will likely be large.
On the other hand, the concentrations of H2 and O2 will be relatively smaller compared to H2O, implying that the denominators will be smaller.
Based on these considerations, the likely magnitude of the equilibrium constant will be large (greater than 1), indicating that d) k > 10^3 is the most suitable choice.
To determine the likely magnitude of the equilibrium constant (K), you need to consider the reaction stoichiometry and the relative concentrations of the reactants and products.
In this case, the reaction is 2H2 (g) + O2 (g) ⇌ 2H2O (g).
The equilibrium constant (K) is calculated using the formula K = [products]^coefficient / [reactants]^coefficient, where the coefficients indicate the stoichiometric ratios from the balanced equation.
From the balanced equation, you can see that the stoichiometric ratio between the reactants and products is 2:1. As a result, to determine the likely magnitude of K, you need to compare the initial concentrations of H2 and O2 to the equilibrium concentrations of H2O.
If the initial concentrations of H2 and O2 are relatively high compared to the equilibrium concentrations of H2O, it indicates that the forward reaction is favored, and the equilibrium constant (K) will have a larger value.
On the other hand, if the initial concentrations of H2 and O2 are relatively low compared to the equilibrium concentrations of H2O, it indicates that the reverse reaction is favored, and the equilibrium constant (K) will have a smaller value.
Now, let's analyze the given answer choices:
a) k < 10 ^-3: This answer choice suggests that the equilibrium constant (K) is less than 10^-3. If the equilibrium concentrations of H2O are significantly higher than the initial concentrations of H2 and O2, this choice could be correct.
b) 10^-3 < K < 10^3: This answer choice suggests that the equilibrium constant (K) lies between 10^-3 and 10^3. If the equilibrium concentrations of H2O are comparable to the initial concentrations of H2 and O2, this choice could be correct.
c) k = 0: This answer choice is incorrect because, as you correctly mentioned, if K = 0, there would be no need to calculate equilibrium. The reaction would only proceed in one direction.
d) k > 10^3: This answer choice suggests that the equilibrium constant (K) is greater than 10^3. If the equilibrium concentrations of H2O are significantly lower than the initial concentrations of H2 and O2, this choice could be correct.
Therefore, based on the given information, the most likely answer choice is b) 10^-3 < K < 10^3. However, to make a definitive conclusion, you would need more information about the initial and equilibrium concentrations of the reactants and products.