The standard enthalpy of diamond is zero at `298K` and `1 atm` pressure.

Standard enthalpy of formation is zero for

Standard enthalpy of formation is non zero for

The stable state of aggregation of carbon at 298K and 1atm pressure is……………

The stable state of aggregation of sulphur at 298K and 1atm pressure is…………….sulphur.

The heat of formation is the change in enthalpy accompanying the formation of a substance fiom its elements at 298 K and 1 atm pressure. Since the anthalpies of elements are taken to be zero, the heat of formation (triangleH) of compounds

The standard enthalpy of Br_(2)(g) is taken to be zero at standard conditions of 298K and 1atm .

The standard enthalpy of formation (Delta_(f)H^(@)) at 298K for methane (CH_(4(g))) is -74.8kJ mol^(-1) . The additional information required to determine the average energy for C-H bond formation would be :

Calculate the equilibrium constant for the following reaction at 298K and 1 atmospheric pressure: C(grap hite) +H_(2)O(l) rarr CO(g) +H_(2)(g) Given Delta_(f)H^(Theta) at 298 K for H_(2)O(l) =- 286.0 kJ mol^(-1) for CO(g) =- 110.5 kJ mol^(-1) DeltaS^(Theta) at 298K for the reaction = 252.6 J K^(-1) mol^(-1)

Let gas (A) present in air is dissolved in 20 moles of water at 298K and 20 atm pressure. The mole fraction of gas (A) in air is 0.2 and the Henry's law constant for solubility of gas (A) in water at 298K is 1×10^5atm.The number of mole of gas (A) dissolved in water will be

The standard state Gibbs free energies of formation of ) C(graphite and C(diamond) at T = 298 K are Delta_(f)G^(@)["C(graphite")]=0kJ mol^(-1) Delta_(f)G^(@)["C(diamond")]=2.9kJ mol^(-1) The standard state means that the pressure should be 1 bar, and substance should be pure at a given temperature. The conversion of graphite [ ) C(graphite ] to diamond [C(diamond)] reduces its volume by 2xx10^(-6)m^(3) mol^(-1). If ) C(graphite is converted to C(diamond) isothermally at T = 298 K, the pressure at which ) C(graphite is in equilibrium with C(diamond), is ["Useful information:"1J=1kg m^(2)s^(-2),1Pa=1kgm^(-1)s^(-2),1"bar"=10^(5)Pa]