EASY
11th ICSE
IMPORTANT
Earn 100

Calculate the enthalpy of formation of acetic acid (CH3COOH) if its enthalpy of combustion is - 867 kJ mol-1. The enthalpies of formation of CO2(g) and H2O(l) are - 393.5 and - 285.9 kJ mol-1 respectively.

Important Questions on Thermodynamics

EASY
11th ICSE
IMPORTANT
Define heat capacity, specific heat capacity and molar heat capacity. How are they related?
MEDIUM
11th ICSE
IMPORTANT
A 5 L cylinder contained 10 moles of oxygen gas at 27°C. Due to sudden leakage through the hole, all the gas escaped into the atmosphere and the cylinder got empty. If the atmospheric pressure is 1.0 atmosphere, calculate the work done by the gas. (1 L atm= 101.3 J)
EASY
11th ICSE
IMPORTANT
Neither the enthalpy change nor the entropy change alone can be used to explain the spontaneity of a reaction. Explain.
MEDIUM
11th ICSE
IMPORTANT

It is planned to carry the reaction, CaCO3(s)  CaO(s) + CO2(g) at 1273 K and 1 bar

Is this reaction spontaneous at this temperature and pressure?

Given,

ΔfH°  values (kJ mol1): CaCO3(s)=1206.9,CaO(s)=635.1,CO2(g)=393.5 S° values (JK1 mol1), CaCO3(s)=92.9,CaO(s)=39.8,CO2(g)=213.7.

MEDIUM
11th ICSE
IMPORTANT

It is planned to carry the reaction, CaCO3(s)  CaO(s) + CO2(g) at 1273 K and 1 bar

Calculate the value of Kp at 1273 K for the reaction.
Given,

ΔfH° (kJ mol1): CaCO3(s)=1206.9, CaO(s)=635.1, CO2(g)=393.5 S° (JK1mol1), CaCO3(s)=92.9, CaO(s)=39.8, CO2(g)=213.7.

HARD
11th ICSE
IMPORTANT

It is planned to carry the reaction, CaCO3(s)  CaO(s) + CO2(g) at 1273 K and 1 bar

Calculate the value of partial pressure of CO2, at equilibrium

Given,

ΔfH°  values (kJ mol1): CaCO3(s)=1206.9,CaO(s)=635.1,CO2(g)=393.5 S° values (JK1mol1), CaCO3(s)=92.9,CaO(s)=39.8,CO2(g)=213.7.

MEDIUM
11th ICSE
IMPORTANT
State the law of thermodynamics that was first formulated by Nernst in 1906. What is the utility of this law? The equilibrium constant for the reaction AB is 1.8 ×10-7 at 298 K. Calculate the value of Gº for the reaction (R = 8.314 J K-1 mol-1). Predict the feasibility of the reaction under standard states.
EASY
11th ICSE
IMPORTANT

Two moles of a perfect gas undergo the following processes :

(i) a reversible isobaric expansion from (1.0 atm, 20.0 L) to (1.0 atm, 40.0 L)

(ii) a reversible isochoric change of state from (1.0 atm, 40.0 L) to (0.5 atm, 40.0 L)

(iii) a reversible isothermal compression from (0.5 atm, 40.0 L) to (1.0 atm, 20.0L)

Sketch with labels each of the processes on the same p-V diagram.