Question

For the reaction `"CO"(g) + "NH"_3(g) rightleftharpoons "HCONH"_2(g)`, if `"3.00 atm"` of `"CO"` and `"1.40 atm"` of `"NH"_3` were allowed to react in a closed container, then if `K_p = 2.70` at a certain temperature, what is `P_(HCONH_2)` at equilibrium?

Answer 1

With everything in a gas phase, we can use the partial pressures as proxies for the molar concentrations.

Explanation:

Set up the ICE Table

`sf(" "" "" "" "" ""CO"" "" "" ""NH"_3" "rightleftharpoons" ""HCONH"_2)`

`sf"Initial"` `sf(" "" "" "3.00" "" "" "1.40" "" "" "" "0.00)`
`sf"Change"` `sf(" "" " -x " "" "" "-x" "" "" "" "+x)`
`sf"Equilibrium"` `sf(" "3 - x " "" "1.4 - x" "" "" "" " x)`

Then put those into the equilibrium expression and solve for x.

`2.70 = x/((3-x)(1.4-x))`

'`x`' will be the desired `sf(HCONH_2)` partial pressure.
You can calculate the equilibrium concentrations of the other gases from it, if desired.