A #7 L# container holds #28 # mol and #12 # mol of gasses A and B, respectively. Groups of three of molecules of gas B bind to five molecules of gas A and the reaction changes the temperature from #150^oK# to #160^oK#. How much does the pressure change?
1 Answer
All of the gas A and some of the gas B will react to produce
The pressure will change by
Explanation:
(we need to assume that the gases are monatomic before the reaction, since we are not told otherwise)
The reaction will be:
That is, 8 mol of reactant gases combine to produce each 1 mol of product gas.
The gases are not present in this ratio, so one will be 'in excess' of the other and be left over after the reaction.
There is much more of gas A than gas B, but we need more of gas B for each reaction, so all the gas B will be used up and some gas A will be left over. After the reaction, the container will include product gas
The reaction in the equation above will occur
That means there will be a total of
We can use the universal gas equation:
Rearranging:
In this case R, the gas constant, and V, the volume of the container, are constant, so we can remove them from the expression:
The pressure will change by