Predict whether the following reactions will be exothermic or endothermic

A) N2(g)+ 3H2(g) --> 2NH3(g)
B) S(g) +O2(g) ---> SO2(g)
C) 2H2O(g) ---->2H2(g) + O2(g)
D) 2F(g) +F2(g)

Bond
H-H 432 kj/mol
N-N(triple bond) 942 kj/mol
O=O 494 KJ/Mol
F-F 155 KJ/mol
H-N 386 KJ/mol
H-O 459 kj/mol
S=O 522 KJ/mol

Respuesta :

Answer:

A) N2(g)+ 3H2(g) --> 2NH3(g)    exothermic

B) S(g) +O2(g) ---> SO2(g)    endothermic

C) 2H2O(g) ---->2H2(g) + O2(g)    endothermic

D) 2F(g) +F2(g)   endothermic

Explanation:

Hello,

By computing the energy difference between the products and reagents for each chemical reaction, one obtains:

A) N2(g)+ 3H2(g) --> 2NH3(g)

ΔrH=2*386 kJ/mol-942 kJ/mol-3*432 kJ/mol=-1466kJ/mol->exothermic

B) S(g) +O2(g) ---> SO2(g)

ΔrH=522 kJ/mol-494 kJ/mol=28kJ/mol->endothermic

C) 2H2O(g) ---->2H2(g) + O2(g)

ΔrH=2*432 kJ/mol+494 kJ/mol-2*459 kJ/mol=440kJ/mol->endothermic

D) 2F(g) --->F2(g)

ΔrH=155kJ/mol>endothermic

Best regards.