Advertisements
Advertisements
प्रश्न
Select the most appropriate option.
The enthalpy of formation for all elements in their standard states is _______.
पर्याय
unity
zero
less than zero
different elements
उत्तर
The enthalpy of formation for all elements in their standard states is zero.
APPEARS IN
संबंधित प्रश्न
Select the most appropriate option.
If the standard enthalpy of formation of methanol is –238.9 kJ mol–1 then entropy change of the surroundings will be _______.
Select the most appropriate option.
Bond enthalpies of H–H, Cl–Cl, and H–Cl bonds are 434 kJ mol–1, 242 kJ mol–1, and 431 kJ mol–1, respectively. Enthalpy of formation of HCl is _______.
Calculate the work done in the decomposition of 132 g of \[\ce{NH4NO3}\] at 100 °C.
\[\ce{NH4NO3_{(s)} -> N2O_{(g)} + 2H2O_{(g)}}\]
State whether work is done on or by the system.
Answer the following question.
Calculate standard enthalpy of reaction,
Fe2O3(s) + 3CO(g) → 2Fe(s) + 3CO2(g), from the following data.
Δf H°(Fe2O3) = - 824 kJ/mol,
Δf H°(CO) = - 110 kJ/mol,
Δf H°(CO2) = - 393 kJ/mol
Calculate the amount of work done in the
1) Oxidation of 1 mole HCl(g) at 200 °C according to reaction.
4HCl(g) + O2(g) → 2Cl2(g) + 2H2O(g)
2) Decomposition of one mole of NO at 300 °C for the reaction
2NO(g) → N2(g) + O2(g)
Answer the following question.
When 6.0 g of O2 reacts with CIF as per
\[\ce{2ClF_{(g)} + O2_{(g)} -> Cl2O_{(g)} + OF2_{(g)}}\]
The enthalpy change is 38.55 kJ. What is the standard enthalpy of the reaction? (Δr H° = 205.6 kJ)
Calculate the work done and comment on whether work is done on or by the system for the decomposition of 2 moles of NH4NO3 at 100 °C
NH4NO3(s) → N2O(g) + 2H2O(g)
Define enthalpy of combustion.
Define enthalpy of neutralization.
Derive the relation between ∆H and ∆U for an ideal gas. Explain each term involved in the equation.
The standard enthalpy of formation of ammonia is −46.0 kJ mol−1. The enthalpy change for the reaction:
\[\ce{2NH3_{(g)} -> 2N2_{(g)} + 3H2_{(g)}}\] is ____________.
What is standard N ≡ N bond enthalpy from following reaction,
\[\ce{N2_{(g)} + 3H2_{(g)} -> 2NH3_{(g)}; \Delta H^0 = - 83 kJ}\]
\[\ce{ΔH^0_{(H-H)}}\] = 435 kJ; \[\ce{ΔH^0_{(N-H)}}\] = 389 kJ
For which of the following ∆U = ∆H?
The difference between heats of reaction at constant pressure and at constanl volume for the reaction
\[\ce{2C6H6_{(l)} + 15O2_{(g)} -> 12CO2_{(g)} + 6H2O_{(l)}}\] at 25°C in kJ
When 4 g of iron is burnt to ferric oxide at constant pressure, 29.28 kJ of heat is evolved. What is the enthalpy of formation of ferric oxide?
(Atomic mass of Fe = 56)
The enthalpy change for two reactions are given by the equations
\[\ce{2Cr_{(s)} + 1.5 O2_{(g)} -> Cr2O3_{(s)}}\];
∆H1 = −1130 kJ ............(i)
\[\ce{C_{(s)} + 0.5 O2_{(g)} -> CO_{(g)}}\];
∆H2 = −110 kJ .........(ii)
What is the enthalpy change, in kJ, for the following reaction?
\[\ce{3C_{(s)} + Cr2O3_{(s)} -> 2Cr_{(s)} + 3CO_{(g)}}\]
In which of the following reactions does the heat change represent the heat of formation of water?
Work done when 2 moles of an ideal gas is compressed from a volume of 5 m3 to 1 dm3 at 300 K, under a pressure of 100 kPa is ____________.
For the reaction, \[\ce{A_{(s)} + 2B_{(g)} -> 5C_{(s)} + D_{(l)}}\], ∆H and ∆U are related as ____________.
If 2 kJ of heat is released from system and 6 kJ of work is done on the system, what is enthalpy change of system?
What is the amount of work done when 0.5 mole of methane, CH4 (g), is subjected to combustion at 300 K? (Given, R = 8.314 JK-1mol-1)
The work done during combustion of 9 × 10-2 kg of ethane, C2H6 (g) at 300 K is ______.
(Given R = 8.314 J deg-1, atomic mass C = 12, H = 1)
Calculate ΔU if 2 kJ heat is released and 10 kJ of work is done on the system.
Define enthalpy.