A #3 L# container holds #5 # mol and #5 # mol of gasses A and B, respectively. Groups of three of molecules of gas B bind to two molecules of gas A and the reaction changes the temperature from #340^oK# to #320^oK#. How much does the pressure change?
1 Answer
We have to take two things into account:
the change in moles and the change in temperature.
Explanation:
(1) change caused by change in number of molecules:
Reaction equation:
So
Since every 3 moles of B will form 1 mole of
Total moles before reaction:
Total moles after reaction:
(mixture of
Pressure change because of amount of matter:
(2) Change caused by temperature change:
Temperature goes down from
Pressure change:
Total change:
Pressure is decreased by a factor of
Or: pressure decreases to
Note:
Of course you could have used the general gas-formula