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VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: Nomvalt on December 01, 2009, 02:25:10 am

Title: What did I do wrong?
Post by: Nomvalt on December 01, 2009, 02:25:10 am: An equilbrium mixture consisting of hydrogen, iodine and hydrogen iodide was analysed. It was found that 1.1 mol of hydrogen and 3.3 mol of hydrogen iodide were present in a 3.0 L container at a temperature of 600 K.
a) If the value of the equlibrium constant, K, is 49 for the reaction:

$H_{2}(g) + I_{2}(g)\rightleftharpoons 2HI(g)$

calculate the concerntration of iodine.

$c = \frac{n}{V}<br />c(H) = \frac{1.1}{3.0}<br />= 0.3666...$
$c(HI) = \frac{3.3}{3.0}<br />= 1.1$
Substituting the values for the concentration of hydrogen gas and hydrogen iodide and the value of 49 for K into:

$K = \frac{[HI]^2}{[H_{2}][I_{2}]}$

we get:

$49 = \frac{(1.1)^2}{0.3666...[I_{2}]}$
$[I_{2}] = \frac{1.21}{49 * 0.3666...}$

$= 0.067346938$

$\approx 0.067 mol L^-1$

However, the correct answer is supposed to be $0.50 mol L^-1$ . Where did I go wrong? :(

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