Which equation is a correctly written thermochemical equation?

C3H8 (g) + 5O2 (g)→3CO2 (g) + 4H2O (l) , ΔH= −2,220 kJ/mol

Fe (s) + O2 (g)→Fe2O3 (s) , ΔH= −3,926 kJ

NH4Cl→NH4 + + Cl−

2C8H18 + 25O2→16CO2 + 18H2O , ΔH= −5,471 kJ/mol

Can someone me with this problem . show your work .

Solve the problem by making up an equation. a man could arrive on time for an appointment if he drove the car at 40 mph; however, since he left the house 15 minutes late, he drove the car at 50 mph and arrive 3 minutes early for the appointment. how far from his house was his appointment?

Simplify the following expression 48^1/2