Chemistry > Thermodynamics and Thermochemistry > 7.0 First Law of Thermodynamics
Thermodynamics and Thermochemistry
1.0 Introduction to Thermodynamics
1.1 Importance of Thermodynamics
1.2 Limitations of Thermodynamics
1.3 Some Basic Terms of Thermodynamics
2.0 Thermodynamic Processes
2.1 Some other important relations of adiabatic process
2.2 Reversible and Irreversible Processes
2.3 Polytropic Process
3.0 Heat $(Q)$
4.0 Work $(W)$
5.0 Internal Energy
6.0 Zeroth Law of Thermodynamic
7.0 First Law of Thermodynamics
8.0 Heat Capacity
9.0 Enthalpy $(H)$ or Heat Content
10.0 Significance of $?H$ and $?E$
11.0 Relationship Between $?H$ and $?E$
12.0 Standard Enthalpy of Reaction
12.1 Molar Enthalpy of Fusion $\left( {\Delta {H_{fus}}} \right)$
12.2 Molar Enthalpy of Vaporisation $(\Delta {H_{vap}})$
12.3 Enthalpy of Sublimation $\left( {\Delta {H_{sub}}} \right)$
12.4 Enthalpy of Formation
12.5 Enthalpy of Combustion $\left( {\Delta {H_c}} \right)$
12.6 Enthalpy of Neutralization $\left( {\Delta {H_{neu}}} \right)$
12.7 Enthalpy of Solution $\left( {\Delta {H_{sol}}} \right)$
13.0 Law of Thermodynamics
14.0 Bond Energy or Bond Enthalpies
15.0 Second Law of Thermodynamic
16.0 Entropy (S)
16.1 Some Important points Related to Entropy
16.2 Entropy Change in Various Thermodynamic Process
16.3 Entropy Change in Phase Transformation
17.0 Spontaneous Processes
18.0 Free Energy (G)
19.0 Enthalpy, Entropy, Free Energy Changes and The Nature of Process
20.0 Standard Free Energy Change
21.0 Coupled Reactions
22.0 Third Law of Thermodynamic
22.1 Third Law of Thermodynamics, Entropy ? Temperature
22.2 Limitations of Third Law of Thermodynamics
23.0 Important Facts
7.2 Calculation of Work done $(W)$
1.2 Limitations of Thermodynamics
1.3 Some Basic Terms of Thermodynamics
2.2 Reversible and Irreversible Processes
2.3 Polytropic Process
12.2 Molar Enthalpy of Vaporisation $(\Delta {H_{vap}})$
12.3 Enthalpy of Sublimation $\left( {\Delta {H_{sub}}} \right)$
12.4 Enthalpy of Formation
12.5 Enthalpy of Combustion $\left( {\Delta {H_c}} \right)$
12.6 Enthalpy of Neutralization $\left( {\Delta {H_{neu}}} \right)$
12.7 Enthalpy of Solution $\left( {\Delta {H_{sol}}} \right)$
16.2 Entropy Change in Various Thermodynamic Process
16.3 Entropy Change in Phase Transformation
22.2 Limitations of Third Law of Thermodynamics
For any expansion against external pressure ${p_{ext'.}}$
$W = - \int\limits_{{v_1}}^{{v_2}} {{P_{ext}}dv} $
Case 1: When V is constant (Isochoric process)
$W = 0,{\text{ }}{q_v} = \Delta E{\text{ }}$
Case 2: When ${P_{ext}}$ is constant (isobaric process)
$W = {\text{ }} - {\text{ }}{P_{ext}}{\text{ }}\Delta V{\text{ }} = {\text{ }}{q_p} = {\text{ }}\Delta E{\text{ }} + {\text{ }}{P_{ext}}{\text{ }}\Delta V$
If process is reversible and isobaric i.e. ${P_{ext}} = {P_{gas}} = {\text{constant}}$
$W = - {P_{ext}}{\text{ }}\Delta V = - {P_{gas}}{\text{ }}\Delta V{\text{ }}{q_p} = \Delta E + P\Delta V$
Case 3: When T is constant (Isothermal expansion)
Case (a): When the process is irreversible isothermal and ${P_{ext}}$ is constant.
$W = - {P_{ext}}{\text{ }}\Delta V$
Case (b): When the process is reversible and isothermal.
$W = - 2.303{\text{ }}nRT{\text{ }}{V_2}/{V_1} = - 2.303nRT{\text{ }}\log {P_1}/{P_2}$
Important Fact: During isothermal expansion for a sample of ideal gas $?E = 0$
Case 4: When $q = 0$ i.e. (adiabatic reversible process)
$W = \frac{{nR\left( {{T_2} - {T_1}} \right)}}{{\gamma - 1}} = \frac{{{P_2}{V_2} - {P_1}{V_1}}}{{\gamma - 1}}$
