Class 11 Chemistry - Chapter Thermodynamics NCERT Solutions | The equilibrium constant for a reaction

In a process, 701 J of heat is absorbed by a system and 394 J ofwork is done by the system. What is the change in internal energy for the process?

For the reaction, 2Cl_(g) → Cl_2(g),what are the signs of ΔH and ΔS ?

For the reaction at 298 K,

2A + B → C

ΔH = 400 kJ mol^-1and ΔS = 0.2 kJ K^-1mol^-1

At what temperature will the reaction become spontaneous considering ΔH and ΔS to be constant over the temperature range?

A reaction, A + B → C + D + q is found to have a positive entropy change. The reaction will be

(i) possible at high temperature

(ii) possible only at low temperature

(iii) not possible at any temperature

(iv) possible at any temperature

The enthalpy of combustion of methane, graphite and dihydrogen at 298 K are, –890.3 kJ mol^–1  , –393.5 kJ mol^–1, and –285.8 kJ mol^–1 respectively. Enthalpy of formation of CH₄(g) will be

(i) –74.8 kJ mol^–1

(ii) –52.27 kJ mol^–1

(iii) +74.8 kJ mol^–1

(iv) +52.26 kJ mol^–1

Calculate the enthalpy change on freezing of 1.0 mol of water at 10.0°C to ice at -10.0°C. Δ_fusH = 6.03 kJ mol^-1 at 0°C.

C_p[H₂O(l)] = 75.3 J mol^-1 K^-1

C_p[H₂O(s)] = 36.8 J mol^-1 K^-1

For an isolated system, ΔU = 0, what will be ΔS?

Calculate the enthalpy change for the process

CCl₄(g) → C(g) + 4 Cl(g)

and calculate bond enthalpy of C – Cl in CCl₄(g).

Δ_vapH⁰(CCl₄) = 30.5 kJ mol^–1.

Δ_fH⁰ (CCl₄) = –135.5 kJ mol^–1.

Δ_aH⁰ (C) = 715.0 kJ mol^–1 , where Δ_aH⁰ is enthalpy of atomisation

Δ_aH⁰ (Cl₂) = 242 kJ mol^–1

Choose the correct answer. A thermodynamic state function is a quantity
(i) used to determine heat changes
(ii) whose value is independent of path
(iii) used to determine pressure volume work
(iv) whose value depends on temperature only.

Enthalpies of formation of CO(g), CO₂(g), N₂O(g) and N₂O₄(g) are –110, – 393, 81 and 9.7 kJ mol–1 respectively. Find the value of Δ_rH for the reaction:

N₂O₄(g) + 3CO(g) → N₂O(g) + 3CO₂(g)

How do you account for the formation of ethane during chlorination of methane?

What are hybridisation states of each carbon atom in the following compounds ?

(i) CH₂=C=O,

(ii) CH₃CH=CH₂,

(iii) (CH₃)₂CO,

(iv) CH₂=CHCN,

(v) C₆H₆

What will be the minimum pressure required to compress 500 dm³ of air at 1 bar to 200 dm³ at 30°C?

What are the common physical and chemical features of alkali metals?

Calculate the molecular mass of the following:
(i) H₂O
(ii) CO₂
(iii) CH₄

Assign oxidation number to the underlined elements in each of the following species:

(a) NaH₂PO₄

(b) NaHSO₄

(c) H₄P₂O₇

(d) K₂MnO₄

(e) CaO₂

(f) NaBH₄

(g) H₂S₂O₇

(h) KAl(SO₄)₂.12 H₂O

What is the basic theme of organisation in the periodic table?

Explain the formation of a chemical bond.

A liquid is in equilibrium with its vapour in a sealed container at a fixed temperature. The volume of the container is suddenly increased.
a) What is the initial effect of the change on vapour pressure?
b) How do rates of evaporation and condensation change initially?
c) What happens when equilibrium is restored finally and what will be the final vapour pressure?

Justify the position of hydrogen in the periodic table on the basis of its electronic configuration.

A certain particle carries 2.5 × 10^–16C of static electric charge. Calculate the number of electrons present in it.

Pay load is defined as the difference between the mass of displaced air and the mass of the balloon. Calculate the pay load when a balloon of radius 10 m, mass 100 kg is filled with helium at 1.66 bar at 27°C. (Density of air = 1.2 kg m^–3 and R = 0.083 bar dm³ K^–1 mol^–1).

How many significant figures should be present in the answer of the following calculations?

(i) 

(ii) 5 × 5.364

(iii) 0.0125 + 0.7864 + 0.0215

Although geometries of NH₃ and H₂O molecules are distorted tetrahedral, bond angle in water is less than that of ammonia. Discuss.

Discuss the consequences of high enthalpy of H-H bond in terms of chemical reactivity of dihydrogen.

An element with mass number 81 contains 31.7% more neutrons as compared to protons. Assign the atomic symbol.

The pH of 0.1M solution of cyanic acid (HCNO) is 2.34. Calculate the ionization constant of the acid and its degree of ionization in the solution.

Calculate the mass of sodium acetate (CH₃COONa) required to make 500 mL of 0.375 molar aqueous solution. Molar mass of sodium acetate is 82.0245 g mol^–1

Why does boron trifluoride behave as a Lewis acid?

Calculate the temperature of 4.0 mol of a gas occupying 5 dm³ at 3.32 bar.

(R = 0.083 bar dm³ K^–1 mol^–1).