Applications of First Law of Thermodynamics

IMPORTANT

Applications of First Law of Thermodynamics: Overview

This Topic covers sub-topics such as Enthalpy, Work Done in Reversible Isothermal Expansion, Work Done in Reversible Adiabatic Process, Graph of Adiabatic Process, Graph of Isobaric Process and, Work Done in Irreversible Adiabatic Process

Important Questions on Applications of First Law of Thermodynamics

MEDIUM
IMPORTANT

3 moles of an ideal gas expands isothermally against a constant pressure of 2 Pascal from 20 L to 60 L.The amount of work involved is

EASY
IMPORTANT

The enthalpy change of a reaction is independent of

HARD
IMPORTANT

q, w, ΔE and ΔH for the following process ABCD for a monoatomic gas are:

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HARD
IMPORTANT

Consider the reversible isothermal expansion of an ideal gas in a closed system at two different temperatures T1 and T2 T1<T2. The correct graphical depiction of the dependence of work done w on the final volume v.

MEDIUM
IMPORTANT

A thermodynamic cycle in the pressure P-volume V plane is given below:
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AB and CD are isothermal processes while BC and DA are adiabatic processes. The same cycle in the temperature T- entropy S plane is :

HARD
IMPORTANT

During the free expansion of an ideal gas in an isolated chamber,
 

MEDIUM
IMPORTANT

A piston filled with 0.04 mol of an ideal gas expands reversibly from 50.0 ml to 375 ml at a constant temperature of 37.0°C. As it does so, it absorbs 208 J of heat. The values of q and w for the process will be

(R=8.314 J/mol K) (ln7.5=2.01)

MEDIUM
IMPORTANT

One mole of an ideal gas (at 25°C ) is expanded from volume 1 L to 4 L at constant temperature. The value of work done (in J), if gas is expanded against vacuum Pext=0?

HARD
IMPORTANT

For next two question please follow the same

Work done by the system in isothermal reversible process is: wrev= -2.303 nRTlogV2V1 . Also in case of adiabatic reversible process work done by the system is given by: wrev=nRγ-1[T2-T1] . During expansion disorder increases and the increase in disorder is expressed in terms of change in entropy ΔS=ΔHT . Both entropy and enthalpy changes obtained for a process were taken as a measure of spontaneity of process but finally it was recommended that decrease in free energy is responsible for spontaneity and ΔH-TΔS.

Which of the following statements are correct:

(1) The expansion work for a gas into vacuum is equal to zero.

(2) 1 mole of a gas occupying 3 litre volume on expanding to 15 litre at constant pressure of 1 atm does expansion work 1.215 kJ.

(3) The maximum work done during expansion of 16 g O2 at 300 K from 5 dm3 to 25 dm3 is -2.01 KJ.

(4) The ΔS for  S L is almost negligible in comparison to ΔS for L G .

(5) ΔS=2.303 nRlogV2V1 (At constant T)

HARD
IMPORTANT

For next two question please follow the same

A sample of an ideal gas is expanded to twice its original volume of 1 m3 in a reversible process for which  α = 5 atm  m - 6   and  C Vm = 20 J K -1 m -1 at constant volume.

The work done during the process may be

HARD
IMPORTANT

2 moles of an ideal gas with C Pm = 5 2 R at 1 atm, 300 K held in cylinder fitted with piston is expanded reversibly and isothermally to three times volume (initially =V). The cylinder placed in an insulated container and pressure returned to 1 atm adiabatically in one step when mechanical equilibrium is reached. Read the passage and answer the questions as single choice correct.

The volume at point C may be

HARD
IMPORTANT

For next two question please follow the same

 2 moles of an ideal gas with CPm=52R at 1 atm, 300 K held in cylinder fitted with piston is expanded reversibly and isothermally to three times volume (initially =V). The cylinder placed in an insulated container and pressure returned to 1 atm adiabatically in one step when mechanical equilibrium is reached. Read the passage and answer the questions as single choice correct.

Δ H process may be

HARD
IMPORTANT

One mol of a non-ideal gas undergoes a change of state (2.0 atm, 3.0 L, 95 K)  (4.0 atm, 5.0 L, 245 K) with a change in internal energy, U = 30.0 L atm. The change in enthalpy (H) of the process in L atm is

EASY
IMPORTANT

Among the following, which expression is most accurate to calculate the work done by gas in reversible isothermal expansion?

MEDIUM
IMPORTANT

On the basis of following data , calculate the heat of reaction (kJ/mol) for the given process.

CH4(g)+2O2(g) CO2(g)+2H2O(g)

BE(CH)=414kJ/mol , BE(O=O)=498kJ/mol,

BE(C=O)=741kJ/mol , BE(OH)=464kJ/mol

EASY
IMPORTANT

If 20 mL of HCl is added to 20 mL of NaOH solution of same strength, 5°C increment in temperature takes place. If 200 mL of same HCl solution is mixed with 200 mL of same NaOH solution, temperature increases by-

MEDIUM
IMPORTANT

Which of the following relationship between x and y will be true when equal volumes of 1 M HCl and 1 M H2SO4 are neutralized completely by dil. NaOH solution and x  kcal and y kcal heat are liberated respectively?

MEDIUM
IMPORTANT

The value of ΔHO-H is 109 kCal/mol. The enthalpy of  formation of 1 mole of water in gaseous state from H(g) and O(g) is:

EASY
IMPORTANT

Adjacent figure shows the force-displacement graph of a moving body, the work done in displacing body from x=0m tox=35m by the shown force is equals to

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MEDIUM
IMPORTANT

An ideal monoatomic gas is taken round the cycle. ABCDA as shown in figure. The work done during the cycle is

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