Question

Can some explain this using ice table?? Calculate `K_c` at this temperature. Provide your answer to two places after the decimal and without units.

At high temperatures, dinitrogen tetroxide gas decomposes into nitrogen dioxide gas. At `500^@ "C"`, a sealed vessel containing `"8.63 M"` of dinitrogen tetroxide gas was allowed to reach equilibrium. At equilibrium, the mixture contained `"3.65 M"` nitrogen dioxide gas.

Answer 1

I got `K_c = 1.96`.

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The reaction was:

`"N"_2"O"_4(g) " "rightleftharpoons" " 2"NO"_2(g)`

`"I"" ""8.63 M"" "" "" "" ""0 M"`
`"C"" "-x" "" "" "" "+2x`
`"E"" "8.63-x" "" "" ""3.65 M"`

Note how the coefficients of each reactant go into the change in concentration... where else will you see them?

`K_c = (2x)^2/(8.63 - x)`

Now, we must already know `x`... But you would only know that once you write out the ICE table.

`x = 3.65/2 "M" = "1.83 M"`

Therefore,

`color(blue)(K_c) = ("3.65 M")^2/("8.63 M" - "1.83 M")`

`= color(blue)(1.96)`

Here the units are `"M"`, i.e. `"M"^2/"M" = "M"`, but we omit the units on purpose.