Which of the following processes areEndothermic?

a. C₂H₂OH(1)→ C₂H₂OH(g)
b. Br₂(1)→→ Br₂(s)
c. CH2(g) +802(g) → 5CO2(g) + 6H₂O(1)
d. NH3(g) →→→ NH₂(1)
e. NaCl(s)→→→ NaCl(1)

1 answer

a. C₂H₂OH(1)→ C₂H₂OH(g) - Endothermic (going from liquid to gas usually requires energy input)
b. Br₂(1)→→ Br₂(s) - Exothermic (going from gas to solid usually releases energy)
c. CH2(g) +802(g) → 5CO2(g) + 6H₂O(1) - Exothermic (production of CO2 and H2O usually releases energy)
d. NH3(g) →→→ NH₂(1) - Endothermic (breaking chemical bonds usually requires energy input)
e. NaCl(s)→→→ NaCl(1) - Endothermic (going from solid to liquid usually requires energy input)