Question- 5.20 mol of Solid A was placed in a 1.00 L sealed container and allowed to decompose into gaseous B and C. The concentration of B steadily increased until it reached 1.40M, Where it remained constant.
A(S) <---> B(g)+C(g)
Then, the container volume was doubled and equilibrium was re-established.
How many moles of A remain?
Not confident which formulas/units I require to solve something like this