Question 1
When 18.5 g of HgO(s) is decomposed to form Hg(l) and O
2(g), 7.75 kJ of heat is absorbed at standard-state conditions. What is the standard enthalpy of formation (ΔH°
f) of HgO(s)?
◦ –90.7 kJ/mol
◦ –7.75 kJ/mol
◦ 0.419 kJ/mol
◦ 27.9 kJ/mol
◦ 143 kJ/mol
Question 2
Which of the following has a ΔH°
f = 0 kJ/mol?
◦ CO
2(g)
◦ O
3(g)
◦ Cl
-(aq)
◦ NH
3(aq)
◦ I
2(s)