Thermodynamics ...

 For which of the following change ΔH ≠ ΔE ?

Δ_rH of which of the following reactions is zero ?

How much heat will be required at constant pressure to form 1.28 kg of CaC₂ from CaO(s) & C(s) ?

Given :

Δ_fH°(CaO, s) = -152 kcal/mol

Δ_fH°(CaC₂, s) = -14 kcal/mol

Δ_fH°(CO, g) = -26 kcal/mol

50.0 mL of 0.10 M HCl is mixed with 50.0 mL of 0.10 M NaOH. The solution temperature rises by 3.0°C Calculate the enthalpy of neutralization per mole of HCl. [take proper assumptions]

The enthalpy of neutralisation of a weak acid in 1 M solution with a strong base is -56.1 kJ mol^-1. If the enthalpy of ionization of the acid is 1.5 kJ mol^-1 and enthalpy of neutralization of the strong acid with a strong base is -57.3 kJ equiv^-1, what is % ionization of the weak acid in molar solution (assume the acid to be monobasic) ?

For the allotropic change represented by the equation C (graphite) → C (diamond), ΔH = 1.9 kJ. If 6 g of diamond and 6 g of graphite are separately burnt to yield CO₂, the heat liberated in first case is

 If x₁, x₂ and x₃ are enthalpies of H - H, O = O and O - H bonds respectively, and x₄ is the enthalpy of vaporisation of water, estimate the standard enthalpy of combustion of hydrogen

NH₃(g) + 3Cl₂(g)  NCl₃(g) + 3HCl(g) ; -ΔH₁

N₂(g) + 3H₂(g)  2NH₃(g) ; ΔH₂

H₂(g) + Cl₂(g)  2HCl(g) ; ΔH₃

The heat of formation of NCl₃ (g) in the terms of ΔH₁, ΔH₂ and ΔH₃ is

The enthalpy of neutralisation of HCl and NaOH is -57 kJ mol^-1. The heat evolved at constant pressure (in kJ) when 0.5 mole of H₂SO₄ react with 0.75 mole of NaOH is equal to

Reaction involving gold have been of particular interest to a chemist. Consider the following reactions.

Au(OH)₃ + 4 HCl → HAuCl₄ + 3H₂O,         ΔH = -28 kcal

Au(OH)₃ + 4 HBr → HAuBr₄ + 3 H₂O,       ΔH = -36.8 kcal

In an experiment there was an absorption of 0.44 kcal when one mole of HAuBr₄ was mixed with 4 moles of HCl. What is the percentage conversion of HAuBr₄ into HAuCl₄ ?

(i) Cis - 2 - butene → trans - 2 - butene,    ΔH₁ 

(ii) Cis - 2 - butene → 1 - butene,  ΔH₂

(iii) Trans - 2 - butene is more stable than cis - 2 - butene.

(iv) Enthalpy of combustion of 1 - butene, ΔH = -649.8 kcal/mol

(v) 9ΔH₁ + 5 ΔH₂ = 0

(vi) Enthalpy of combustion of trans 2 - butene, ΔH = -647.0 kcal/mol

Q. The value of ΔH₁ & ΔH₂ in Kcal/mole are

The reaction CH₄(g) + Cl₂(g) → CH₃Cl(g) + HCl(g) has ΔH = -25 kCal.

From the given data, what is the bond energy of Cl - Cl bond

From the following data at 25°C

Which of the following statement(s) is/are correct :
Statement(a) : Δ_rH° for the reaction H₂O(g) → 2H(g) + O(g) is 925 kJ/mol
Statement(b) : Δ_rH° for the reaction OH(g) → H(g) + O(g) is 502 kJ/mol
Statement(c) : Enthalpy of formation of H(g) is-–218 kJ/mol
Statement(d) : Enthalpy of formation of OH(g) is 42 kJ/mol

The standard molar enthalpies for formation of cyclohexane (l) & benzene (l) at 25°C are -156 & + 49 kJ/mol respectively. The standard enthalpy of hydrogenation of cyclohexane (l) at 25° is -119 kJ mol^-1. Use these data to estimate the magnitude of the resonance energy of benzene.

For hypothetical reaction -

A(g) + B (g) → C (g) + D (g)

Which of the following statements is correct -

ΔH for CaCO_3(s) → CaO_(s) + CO_2(g) is 176 kJ mol^-1 at 1240 K. The ΔU for the change is equal to :

Select the correct order in the following :

When enthalpy of reactants is higher than product then reaction will be

In the combustion of 4g. of CH₄, 2.5 K cal of heat is liberated. The heat of combustion of CH₄ is -

Ammonium nitrate can decompose with explosion by the following reaction.

NH₄NO₃ (s) → N₂O (g) + 2H₂O ;

ΔH = -37.0 KJ/mol

Calculate the heat produced when 2.50g of NH₄NO₃ decomposes -

From the following data, the heat of formation of Ca(OH)_2(s) at 18°C is ………..kcal:

For the process, melting of ice at 260 K the ΔH is -

 Enthalpy of formation of compound is -

 The enthalpy of combustion of a substance -

HA + OH^- → H₂O + A^- + q₁ kJ

H⁺ + OH^- → H₂O + q₂ kJ

The enthalpy of dissociation of HA is

The value of ΔH_sol. of BaCl₂(s) and BaCl₂. 2H₂O (s) are – a kJ and b kJ respectively. The value of ΔH _Hydration of BaCl₂ (s) is-

A solution of 500 ml of 0.2 M KOH and 500 ml of 0.2 M HCl is mixed and stirred; the rise in temperature is T₁. The experiment is repeated using 250 ml of each solution, the temperature raised is T₂. Which of the following is true -

The net heat change in a chemical reaction is same whether it is brought about in two or more different ways in one or several steps. It is known as -

According to Hess's Law the thermal effect of a reaction depends on -

How many kcal of heat is evolved by the complete neutralisation of one mole sulphuric acid with NaOH -