Answer
(a) 125 kJ
(b) 188 kJ
(c) 125 kJ
(d) 208 kJ
Work Step by Step
Based on the given data, we can write
Heat $=\frac{-125\,kJ}{2\,mol\,A}=\frac{-62.5\,kJ}{1\,mol\,A}=\frac{-62.5\times3\,kJ}{3\,mol\,A}=\frac{-125\,kJ}{3\,mol\,B }=\frac{-41.667\,kJ}{1\,mol\,B}=\frac{-41.667\times5\,kJ}{5\,mol\,B}$
Negative sign indicates that the heat is emitted.
(a) When 2 mol A reacts completely, 125 kJ heat is emitted.
(b) When 3 mol A reacts completely, $62.5\times3=188$ kJ heat is emitted.
(c) When 3 mol B reacts completely, 125 kJ heat is emitted.
(d) When 5 mol B reacts completely, $41.667\times5=208$ kJ heat is emitted.