5.00 mol of solid A was placed in a sealed 1.00-L container and allowed to decompose into gaseous B and C. The concentration of B steadily increased until it reached 1.10 M, where it remained constant. Then, the container volume was doubled and equilibrium was re-established. How many moles of A remain?

Question

5.00 mol of solid A was placed in a sealed 1.00-L container and allowed to decompose into gaseous B and C. The concentration of B steadily increased until it reached 1.10 M, where it remained constant. Then, the container volume was doubled and equilibrium was re-established. How many moles of A remain?
A(s)--> B(g)+C(g)

guru · Accepted Answer

just multiply the concentration of Bx2=1.10Mx2L=2.2moles and then subtract the moles of A from calculated moles of B 5.00-2.2=2.8moles