True a negative change in enthalpy means an exothermic reaction
Answer:
The total energy change, ΔE, in kilojoules = -61.93 kJ
Explanation:
Relationship between ΔH, ΔE and work done is given by first law of thermodynamics.
ΔE = ΔH - PΔV
Where,
ΔH = Change in enthalpy
ΔE = Change in internal energy
PΔV = Work done
Given that,
ΔH = -75.0 kJ = -75000 J
P = 43.0 atm
ΔV = Final volume - initial volume
= (2.00 - 5.00) = -3.00 L
PΔV = 43 × (-3.00) = -129 L atm
1 L atm = 101.325 J
-129 L atm = 129 × 101.325 = -13071 J
So ,
ΔE = ΔH - PΔV
= (-75000 J) - ( -13071 J)
= -75000 J + 13071 J
= -61929 J
Total energy change, ΔE = -61.929 kJ
Aluminium metal will readily react with water at room temperature to form aluminium hydroxide and hydrogen
