Ans: To find the value of ΔH for the given reaction:
Fe2O3(s) + CO(g) → 2FeO(s) + CO2(g)
Hess's Law, which states that the enthalpy change for a reaction is the same regardless of whether it occurs in one step or through a series of intermediate steps.
Step1 :
Reverse the 2nd equation:
Fe(s) + CO2(g) → FeO(s) + CO(g) (Note that we have reversed the second reaction and changed the sign of ΔH)
Step 2: Multiply the enthalpy of the 2nd equation:
2Fe(s) + 2CO2(g) → 2FeO(s) + 2CO(g), ΔH = 16.5x2= 33 kJ
Step 3: Now add both the equation
ΔH(target reaction) = ΔH(step 1) + ΔH(step 2)
= -26.8 + 33
= 6.2kJ
The molarity of a 70% (mass/mass) aqueous solution of a monobasic acid (X) is:
Given below are some nitrogen containing compounds:
Each of them is treated with HCl separately. 1.0 g of the most basic compound will consume ....... mg of HCl.
(Given Molar mass in g mol\(^{-1}\): C: 12, H: 1, O: 16, Cl: 35.5.)
List-I | List-II | ||
(A) | 1 mol of H2O to O2 | (I) | 3F |
(B) | 1 mol of MnO-4 to Mn2+ | (II) | 2F |
(C) | 1.5 mol of Ca from molten CaCl2 | (III) | 1F |
(D) | 1 mol of FeO to Fe2O3 | (IV) | 5F |
Thermodynamics in physics is a branch that deals with heat, work and temperature, and their relation to energy, radiation and physical properties of matter.
A thermodynamic system is a specific portion of matter with a definite boundary on which our attention is focused. The system boundary may be real or imaginary, fixed or deformable.
There are three types of systems:
A system undergoes a thermodynamic process when there is some energetic change within the system that is associated with changes in pressure, volume and internal energy.
There are four types of thermodynamic process that have their unique properties, and they are:
The Zeroth law of thermodynamics states that if two bodies are individually in equilibrium with a separate third body, then the first two bodies are also in thermal equilibrium with each other.
The First law of thermodynamics is a version of the law of conservation of energy, adapted for thermodynamic processes, distinguishing three kinds of transfer of energy, as heat, as thermodynamic work, and as energy associated with matter transfer, and relating them to a function of a body's state, called internal energy.
The Second law of thermodynamics is a physical law of thermodynamics about heat and loss in its conversion.
Third law of thermodynamics states, regarding the properties of closed systems in thermodynamic equilibrium: The entropy of a system approaches a constant value when its temperature approaches absolute zero.