Calculate a lattice energy for CaH2 using the following information.
Eea for H = -72.8 kJ/mol
Ei1 for Ca = +589.8 kJ/mol
Ei2 for Ca = +1145 kJ/mol
heat of sublimation for Ca = +178.2 kJ/mol
bond dissociation energy for H2 = +435.9 kJ/mol
net energy change for the formation of CaH2 from its elements = -186.2 kJ/mol
My workCa(s)-> Ca (g) for
178.2 kj/mol
Ca(g)->Ca+ for
589.8kj/mol
Ca+ -> Ca2+ for
1145 kj/mol
H2(g)-> H2(g) for
435.9 kj/mol
H-> H- for
( -72.8*2 )
(Ca2+) + 2H- „³ CaH2 for -U
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Net change
-186.2 kj/mol -U= -178.2-589.8-1145-435.9+(72.8*2)-186.2 = -2389.5 kj/mol
U= 2389.5 kj/mol
What am I doing wrong here?