3 kmol of gas A and 4 kmol of gas B are held in separate but equal volume containers. When they are mixed in a new container, again of equal volume the pressure reading is 10 bar. What is the partial pressure of A?
At the same conditions, pressures of gases are directly proportional to their amounts (ideal gas law), and the total pressure is equal to the sum of partial pressures of each gas (Dalton's law). Let x be the partial pressure of 1 kmol of a gas. Then,
3x + 4x = 10;
7x = 10;
x = 1.4286.
Therefore, the partial pressure of A is "3x=4.29\\ bar"
Answer: 4.29 bar