DeltaH and DeltaU are nearly the same in all the following processes except
a.F2(g)+H2(g) --> 2HF(g)
b.3O2(g) --> 2O3(g)
c.CuO(s) +H2(g) --> Cu(s) +H20(g)
d.CH4(g) +CI2(g) --> CH3Cl(g) +HCl(g)
e.C6H6(s) --> C6H6(l)
Is delta U the change in energy?
Then delta H = delta U + P*delta V
Look for the processes in which the work (P*delta V) is zero (number of moles doesn't change or volume doesn't change). In that case, delta H = delta U.
To determine which of the given processes have similar values for ΔH and ΔU, we need to understand the definitions of ΔH and ΔU.
ΔH (change in enthalpy) is the heat exchanged with the surroundings during a chemical reaction at constant pressure. It takes into account the change in internal energy (ΔU) and the work done (PΔV).
ΔU (change in internal energy) is the change in the total energy of a system. It includes the changes in kinetic energy and potential energy of the particles within the system.
Now, let's analyze each process:
a. F2(g) + H2(g) --> 2HF(g)
This is a reaction that involves the formation of new chemical bonds. It releases energy in the form of heat, making it an exothermic reaction. Both ΔH and ΔU will be negative.
b. 3O2(g) --> 2O3(g)
This process corresponds to the formation of ozone from oxygen molecules. It is an endothermic reaction, meaning it absorbs energy in the form of heat. Both ΔH and ΔU will be positive.
c. CuO(s) + H2(g) --> Cu(s) + H2O(g)
This reaction involves the reduction of copper(II) oxide by hydrogen gas. It releases energy in the form of heat, making it an exothermic reaction. Both ΔH and ΔU will be negative.
d. CH4(g) + Cl2(g) --> CH3Cl(g) + HCl(g)
This reaction corresponds to the chlorination of methane. It is an exothermic reaction, releasing energy in the form of heat. Both ΔH and ΔU will be negative.
e. C6H6(s) --> C6H6(l)
This process represents the phase change from solid benzene to liquid benzene. It involves a change in physical state rather than a chemical reaction. ΔH represents the enthalpy change associated with the phase change, while ΔU represents the internal energy change during the phase change. Both values will be different, making this process the exception where ΔH and ΔU are not nearly the same.
Therefore, the correct answer is (e) C6H6(s) --> C6H6(l).