Given ∆H° for the following reactions:H2(g)+O2(g)➡️2H2O(l):Cu(s)+1/2 O2(g)➡️CuO(s)_What further data is needed, if any,for calculation of ∆H° for the following reactions? CuO(s)+H2(g)➡️Cu(s)+H20(g)

1 Answer
Mar 27, 2018

It is needed to eliminate liquid water by adding an electrolysis reaction and a gas water formation equations to the previous equation

Explanation:

German Henri Hess, in 1840, principle states:
The enthalpy of a given chemical reaction is constant, regardless of the reaction happening in one step or many steps. So, it is possible to get a reactional enthalpy from several reactions.

Flip 2nd reaction and adding both:
#CuO(s)# -----> #Cu(s)# + #0.5O_2(g)#
#H_2(g)# + #O_2(g)#
-----> #2H_2 O(g)#

#=>#

#CuO(s)# + #O_2(g)#__-----> #Cu(s)# + #2H_2 O(L)# + #0.5O_2(g)#

It is needed to eliminate liquid water by adding an electrolysis reaction and a gas water formation equations to the previous equation

#2H_2 O (L)# ----> #2H_2 (g)# + #2O (g)#
#H_2 (g)# + #O (g)#
----> #H_2 O (g)#

#=>#Finally,
#CuO(s)# + #H_2(g)#__-----> #Cu(s)# + #H_2 O(g)#