Answer the following:?

Question

Label each reaction as exothermic or endothermic ('exo' ir 'endo') and according to whether work is done on or by the system, or no work is doen at all ('on', 'by' or 'none')?

Pick either 'exo-none', 'exo-on', 'exo-by' or 'endo-by' for EACH of the following reactions:

a. N2(l) -> N2(g)
b. Cl2(aq) + 2KBr(aq) -> 2KCl(aq) + Br2(aq)
c. Zn(s) + 2HCl(aq) -> ZnCl2(aq) + H2(g)
d. NH3(g) + HCl(g) -> NH4Cl(s)
e. S(s) + 3/2O2(g) -> SO3(g)

Answer 1

a. N2(l) -> N2(g) 'endo-by'
b. Cl2(aq) + 2KBr(aq) -> 2KCl(aq) + Br2(aq)
I do not believe this reaction --- it does not occur that way.
c. Zn(s) + 2HCl(aq) -> ZnCl2(aq) + H2(g) 'exo-by'
d. NH3(g) + HCl(g) -> NH4Cl(s) 'exo-on'
e. S(s) + 3/2O2(g) -> SO3(g) 'exo-on'

Answer 2

a. exo-by
b. exo-none
c. exo-by
d. endo-on
e. exo-by