The enthalpies of all elements in their standard states are:
(iii) < 0
(iv) different for each element
`N_(2(g)) + 3H_(2(g)) -> 2NH_(3(g))`; ΔrHθ = –92.4 kJ mol–1
What is the standard enthalpy of formation of NH3 gas?
The reaction of cyanamide, NH2CN(s),with dioxygen was carried out in a bomb calorimeter, and ΔUwas found to be –742.7 kJ mol–1at 298 K. Calculate enthalpy change for the reaction at 298 K.
`NH_2 CN(g) + 3/2 O_2(g) -> N_2(g) + CO_2(g) + H_2O(1)`
Calculate the standard enthalpy of formation of CH3OH(l) from the following data:
CH3OH(l) + `3/2` O2(g) →CO2(g) + 2H2O(l) ; ΔrHθ = –726 kJ mol–1
C(g) + O2(g) →CO2(g) ; ΔcHθ = –393 kJ mol–1
H2(g) +`1/2` O2(g) → H2O(l) ; ΔfHθ = –286 kJ mol–1.
Enthalpy of combustion of carbon to CO2 is –393.5 kJ mol–1. Calculate the heat released upon formation of 35.2 g of CO2 from carbon and dioxygen gas.
Enthalpies of formation of CO(g), CO2(g), N2O(g) and N2O4(g) are –110 kJ mol–1, – 393 kJ mol–1, 81 kJ mol–1 and 9.7 kJ mol–1 respectively. Find the value of ΔrH for the reaction:
N2O4(g) + 3CO(g) → N2O(g) + 3CO2(g)
Calculate the enthalpy change on freezing of 1.0 mol of water at 10.0°C to ice at –10.0°C. ΔfusH = 6.03 kJ mol–1 at 0°C.
Cp[H2O(l)] = 75.3 J mol–1 K–1
Cp[H2O(s)] = 36.8 J mol–1 K–1