K c = 6.5 x 10 2 at a particular temperature for a reaction: 2 NO(g) + 2 H(g) ⇌ N 2 (g) + 2 H 2 O(g). Calculate K c at same temperature for the following reaction: 1/3 N 2 (g) + 2/3 H 2 O(g) ⇌ 2/3 NO(g) + 2/3 H(g).

Here in this practice question, we're told that kc equals 6.5 times 10 to the 2 at a particular temperature for this reaction. So here we have 2 moles of No gas reacting with 2 moles of H2 gas to produce n2 gas plus 2 moles of water vapor. We now need to calculate the new K c at the same temperature for this new reaction. So if we take a look here what changes have we done? Well, we see that our reactants are now products, and we see that our products are now reactants. So we can say for sure we've reversed the reaction. When we reverse the reaction we get the inverse of our equilibrium constant K C. What other changes have occurred? Well here if we take a look these were 2 and now they're each 2 thirds. This was a 1, now it's 1 third. This is a 2 and now it's 2 thirds, so we also divided by 3. Remember, when we divide by a number it becomes the reciprocal that reciprocal becomes the factor, meaning that we're gonna have K inversed, but then because we divide it by 3 that answer is taken to the 1 third. So we're gonna say now our UKC equals 6.5 6.5 times 10 to the 2. Let's do the inverse of that first. When we do that we get 0.001538 and then we need to take that to the 1 third. So raise this to the 1 third power, and that gives me my final answer point 1154. Since 6.5 times 10 to the 2 has 2 sig figs, we round this to 0.12. So 0.12 here would be our final answer.

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16. Chemical Equilibrium

Using Hess's Law To Determine K

General Chemistry

16. Chemical Equilibrium

Using Hess's Law To Determine K

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Multiple Choice

K_c = 6.5 x 10² at a particular temperature for a reaction: 2 NO(g) + 2 H(g) ⇌ N₂(g) + 2 H₂O(g). Calculate K_c at same temperature for the following reaction: 1/3 N₂(g) + 2/3 H₂O(g) ⇌ 2/3 NO(g) + 2/3 H(g).

8.7

0.12

0.54

3.6×10^–9

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Verified step by step guidance

Identify the original reaction and its equilibrium constant (Kc): 2 NO(g) + 2 H(g) ⇌ N2(g) + 2 H2O(g) with Kc = 6.5 x 10^2.

Recognize that the new reaction is a transformation of the original reaction. The new reaction is: 1/3 N2(g) + 2/3 H2O(g) ⇌ 2/3 NO(g) + 2/3 H(g).

Determine the relationship between the original and new reactions. Notice that the new reaction is the reverse of the original reaction, scaled by a factor of 1/3.

Apply the rule for reversing a reaction: If a reaction is reversed, the new Kc is the reciprocal of the original Kc. Therefore, for the reverse reaction, Kc' = 1 / (Kc).

Apply the rule for scaling a reaction: If a reaction is scaled by a factor of n, the new Kc is the original Kc raised to the power of 1/n. Therefore, for the scaled reaction, Kc'' = (Kc')^(1/3).